@Rain Woman said "TT should have asked if he was disabled rather than kick him down to dependent"
It does ask that. You just missed it. Go back and edit the dependent.
@Rain Woman said "This year big money is involved"
No. Even disabled, he must be under 17 to get the 2020 stimulus ($500 + $600)
@Opus 17 said "If your grandchild has more than $4300 of taxable income to report, they can’t be a qualifying child dependent and will be a qualifying relative dependent"
I don't think that's right. His disability makes him a qualifying child regardless of income or age. He just needs to live with the grandparents and not pay more than half his own support. It's a qualifying relative that can't have more than $4300 of income.
@Opus 17 said "there is very little difference in tax benefit between being a qualifying child or a qualifying relative dependent"
A qualifying child qualifies the taxpayer for child based EIC
