If you define "insane" in the colloquial sense of "unbelievable" or "amazing" or "astounding", then the word works for both sentences. If you define it as "clinically crazy" or "no grip on reality", then it doesn't work for both sentences. I think the gp is clearly going for the prior, not the latter.
Yes the word would work in both, but saying someone has an amazing live still isn't the same as saying that somebody is amazing.
GP was talking about the life he has, not the talent he has, so the "insanity" isn't comparable between his life and that of a child who is talented but has a normal life.