I think he has it right, because the 's is actually "read how Andy is overcoming his mental illness", where the text where you edited it is not correct grammer:
Read how Andy overcome his mental illness
It would have to be overcame or has overcome. That would work if he already overcame it, and was not going though it (I'm not sure which...).
You've got quite a long front page. Maybe reduce the amount of posts, or have post excerpts showing (if you want to know how, I'd be glad to tell you).
