What the Tuohys did with their pretend adoption was wrong, but it was not racism.
Their claim to have adopted him was wrong, when they just put him under conservatorship. That was probably a heartfelt sentiment, as opposed to a legal standing. They made him as much of a son as they could.
Pretend adoption?
It was always a guardianship so that they could take him in and provide him help with basic sustenance and tutors without incurring the wrath of the NCAA. He even specifically acknowledges, describes, and elaborates on it in his 2011 book.