That led to a seven-hour surgery followed by further complications.
"Nothing seems to be going smoothly at the moment," says Amanda.
Jacob was first diagnosed with synovial sarcoma in 2016, and had to have surgery, radiotherapy and chemotherapy.
In 2019, he and his family were told the cancer had returned and it was terminal.
"They said he would have three to five years," adds Amanda.
"Just putting a timeframe on someone's life, it's really hard to deal with."
She said when she got the phone call from the doctor to say Jacob had two more tumours, it was devastating.
"He was hoping and we were hoping that he was just going to be this miracle.
"Like he was going to live and everything was going to be all right.
"When you get told there's two more tumours, it's like a slap back to reality, really."
Things were made more difficult by lockdown, as Amanda would normally be able to spend time with a friend to help her through it.
"Sometimes you just need a break to go and vent and cry.
"I've done a lot of crying over the last couple of weeks.
"I try not to do it in front of the kids too much but not being able to go to my best friend's house just to have that cry, that's been really hard."
She's grateful for all the support she's had from friends in Dannevirke, as well as the community.
"The community is amazing. It makes you feel loved. It makes you feel that everything will be okay."
Her husband Greg's father Kevin is staying in Dannevirke to help look after the three other children and there have been plenty of meals and baking dropped off at the gate.
Her younger children have found the separation difficult, and not just because their parents are with Jacob while he's still in hospital.
"With the lockdown, they were trying to find their feet with schoolwork and stuff and not seeing their friends – they're 14, 10 and nine, so they love their friends.
"And then us saying grandad's coming because we have to go to Auckland and they've been worried about us going to Auckland.
"Thank God for video calling."
During the last lockdown the couple were able to stay in Ronald McDonald House but this time they have had to stay off-site at a motel.
"Normally when you come up here you know when you go into Ronald McDonald House you know what you've got and what you need. This time we had no idea what motel we'd be in, if we had an oven or anything."
Starship Hospital staff had been amazing, allowing both parents to stay with Jacob.
"I don't know whether it's because Jacob is terminal that they make a few extra allowances, but I'm normally up here and his dad can come for as long as he wants as well."
Amanda has created a Givealittle page for donations.
"If Jacob wants something, we want to be able to give it to him."
Visit: https://givealittle.co.nz/cause/terminal-cancer-relapse.