But he is not completely ignoring his aunt's big day. In his zeal to spread the word, he is planning to develop a potent new hybrid strain of cannabis to mark the wedding, called Markle's Sparkle. And should Prince Harry and his bride ever visit Tyler at his home in Grant's Pass, Oregon, he will be 'more than happy' to offer them a sample.
Tyler is not the only member of his family involved with marijuana. His brother TJ, 26 – another of Meghan's nephews – gives it to his dog for pain relief. Their mother Tracy, 52, has a job selling advertising, and many of her clients are marijuana dispensaries.
Tyler and TJ are the sons of Meghan's half-brother Thomas Markle Jr. Tracy is Thomas's former wife.
Tyler says he smoked his first joint at high school but no longer uses cannabis. Recreational marijuana was made legal in Oregon in 2015, since when Tyler has become 'fully immersed' in the booming business, from brokering land for growers (for which he takes a hefty commission) to advising growers on the type and strain of plants to grow, to working out complex watering and lighting systems.
He has even built some of the 'grow facilities' that now dot the lush Oregon landscape.
Tyler took The Mail on Sunday to a pot farm called the Southern Oregon Cannabis Connection, run by his best friend and business partner Fred Tamayo, 49. The three-acre growing facility comes complete with a 6,000 square foot warehouse as well as two retail stores, and employs 25 people.
The stores offer customers hundreds of products ranging from traditional pre-rolled joints to pot-infused gummy bears, oils, vapourisers and pot-laced cookies and popcorn.
Prices range from just £3.50 ($6.80 NZD) for a single joint to £230 ($445 NZD) for several grams of the most potent oil. A lemon doodle cookie two-pack costs £16 ($30 NZD) while "head trip mango guava gummies" are £14 ($27 NZD).
OAPs and military veterans are offered a ten per cent discount.
Read more: • Meghan Markle's brother is arrested
The business is worth about £3.5 million (approx $60m NZD), and Tyler is now paid a commission for sales and marketing services. He was previously paid for finding the land and helping to build the facility.
Tamayo, a divorced father-of-four, was involved in the illegal marijuana trade from aged 17 and was jailed for a year in 2008 after drug enforcement agents found him illegally growing more than 1,000 cannabis plants in bunkers. By 2015, he had obtained a legal recreational grower's licence.
Next month, when the outdoor growing season begins, Tyler, a licensed medical marijuana grower, will plant the legal limit of 48 marijuana plants on his property – pot he will then sell to patients under Oregon's medical marijuana laws.
Oregon became the first state to decriminalise marijuana for personal use and has been at the forefront of legalising both medical and recreational marijuana.
Indeed, since the state legalised recreational marijuana three years ago, it has been flooded with growers to the point there is now a glut of legal pot. Prices have plummeted and many small producers have gone out of business. "The black market in pot has disappeared," Tyler says.
Meghan's nephew openly addresses the criticism from medical experts that it serves as a 'gateway drug' and can permanently affect the brain. A recent study by Professor Sir Robin Murray, from the Institute of Psychiatry at King's College London, warned that new super-strength cannabis could lead to a medical 'ticking time bomb' in Britain because of the terrible toll it can take on the brain.
Skunk cannabis is four times more potent than the cannabis of the 1980s, and Prof Murray warned that regular smokers have a 'significant increased risk' of developing long-term mental-health issues such as psychosis or schizophrenia.
"Yes, the strains are way more potent now," Tyler admits. "But I would argue against it being a gateway drug. Alcohol and tobacco are far more harmful. Prescription pills kill millions in Britain and America every year. Marijuana can help people coming off opioid painkillers."
He says a wealth of products which do not contain the mind-altering chemical THC (tetrahydrocannabinol) but do have in them the medicinal CBD (cannabidiol) used in oils, salves and creams for pain relief "are the future". "We are learning more and more about the medicinal benefits, particularly of products containing CBD," he says.
"I know this is a controversial subject but I'm proud to be involved at the start of an industry that will be worth billions and billions of dollars and could help people around the world.
"Oregon is at the forefront of a revolution and we've proved legalising recreational marijuana works and doesn't make society descend into chaos."
Tyler, who last spoke to Meghan three years ago but recalls her babysitting him and his brother regularly when they were children, adds: "Meghan grew up in California and I am sure has an American view on pot.
"I know in England that marijuana is still a taboo subject but it's more normal to us here because we grew up around it in high school. Everybody experiments with it here.
"Prince Harry enjoys a good party. I'd be happy to show them around if they ever come out here and educate them on the medicinal benefits of marijuana which helps everything from post-traumatic stress syndrome to insomnia to pain in cancer patients."
Tracy, who will join her sons as a commentator on the Royal Wedding for Good Morning Britain, sells radio advertising for Opus Broadcasting. "I represent 11 dispensaries and the money they generate in taxes is revitalising the local economy," she says.
Tracy is a recovering alcoholic and drug addict, and says she is a firm believer in 'all the positive things' legalisation of marijuana has brought to Oregon, citing the millions in tax revenue that has been given to schools, homeless shelters and to build new infrastructure.
"A properly regulated industry is the way to go," she adds. "I hope people in England can see what we are doing here. We haven't all turned into pot-tokeing zombies. Instead we're creating a strictly regulated industry which has the potential to inject billions of dollars into the economy."
Tracy says she has seen first-hand how medical marijuana has 'saved' a lot of people.
"It's a miracle drug that can help in so many ways. And it's natural. By making it legal you can enforce laws and keep the product and consumers safe. It's a win-win. What happens in America normally makes its way to the UK later. Well, the sky hasn't fallen in here."
One of Tracy's clients, Medford Council member Clay Bearnson, is the first elected official in Oregon to own a dispensary, Oregon Farmacy. Tracy adds: "I hope we get a chance to talk to Meghan and Harry about it one day. I'm sure they would be fascinated to see all the great things you can do with pot, once it's legalised and properly regulated."
