Mrs Armer said they had been doing fundraising at his kindergarten, Rotorua Community Creche, and so he understood the concept that it was an option if there was something you could not afford.
She said she had told him if that was what he wanted to do then he would have to organise it, and thought it was going to be "by-the-by".
However, he rang family members and close friends to ask them if there were jobs he could do to fundraise.
Tasks Fletcher ended up undertaking included mowing the lawns, sweeping out a car port, baking cakes, cleaning the bathroom and collecting firewood.
Mrs Armer said a couple of the staff members at Ranolf Medical Centre also found out about Fletcher's fundraising and made a donation.
Fletcher made enough money to buy 12 pairs of "jarmies" and then rang Anneke Slager, a public health nurse at the Lakes District Health Board, who said she was able to find homes for them with children who had rheumatic fever.
Mrs Armer said they went out to find the best deal they could and bought the pyjamas from The Warehouse.
"He really wanted them to be brand new and in a packet."
She said initially she was really surprised and thought it would not come to anything.
"It did surprise me how he actually went through the whole plan and saw it through."
Mrs Armer said they would like to think it has inspired and motivated other children to help other people.
"Hopefully it's inspired others to do more. It's about just being kind and helping."
Fletcher was featured on ONE News' Good Sorts section on Sunday with reporter Hadyn Jones for his fundraising efforts.
Fletcher said it had been fun to do the fundraising and he watched the Good Sorts footage with his friends in class at Lake Rerewhakaaitu School.
His teacher Jhana Brash said next term the class would be looking at what they could do to provide for other children who weren't as blessed as them, following Fletcher's fundraising.
"He's quite an inspiration."