My sister-in-law was a schizophrenic and died two years ago. We are concerned that my two nephews who were also brought up by her mother, herself not a very stable person, might inherit this illness. Especially the younger one who ,apart from throwing tantrums , seems to miimc some of his mother's actions, though she died when he was less than two. We are really nervous that he might inherit this illness ,my very old parents having to take care of him and my brother without any help. My brother himself is not at all an ideal father, though he is not otherwise disabled . My older nephew is fifteen years older than the kid, and he himself has some of his mother's qualities like the " flat affect " and seeming inability to understand or accept any rational thoughts. He just listens without any reaction or emotion or discussion - it is like talking to a zombie .She was the same before she got really worse and violent. We do not want the child to go down the same way. I am an experienced woman of 53 and my brother is 56 . Having seen my sister-in-law for 20 years, I am worried . Should my brother refer the child to a doctor  and will the doctor be able to diagnose anything ? The child is now being taken care of very well, which was not the case when his mother was alive. He has also been in play- school for more than a year now but  at 4, shouldn't he be growing out of tantrums and weird actions like hitting his father and grandparents, pulling his own hair and hitting himself? Some of these things he might have picked up from his mother's mother . But he has been away from her for the past 6 months now.