@501bob,
That therapist was wrong! It might be too late to help your daughter, if she won't accept your help or make changes to better her life, but you have two grandsons who might need you dearly.
They should not grow up in such unstable and violent environment and
I think you should be there for them. You are saying that childcare is provided, but why don't you take over and do that? Be a good, stable influence in their lives and perhaps be a (grand)father figure for them,
since neither father is involved in their lives.