Since the kid is in temporary custody, both his parents are absent and/or screwed up, and the kid is obviously totally screwed up.
If you are foster parents, then no, you are not responsible. Morally, anyway. Who knows about the likely totally screwed up legal system where you live would say.
If you are the grandparents, then quite possibly you have some responsibility if you screwed up the parent who screwed up the kid.
I will bet that the root cause of this is some female got pregnant, you if you are the grandparent, and the mother. Because of religious beliefs, one or both did not get an abortion, even knowing that you/she had no way to take care properly of the kid(s).
Religion is evil.