I Am Very Concerned That My 8 Year Old Grandson

I am very concerned that my 8 year old grandson still sleeps with his mother. Is it considered child abuse or even sexual abuse. I have tried to talk to her about it and her reaction to my question is that he is her baby. When I was dropping them off last night she made a comment that she can't wait to go home and snuggle with her little snuggle bug (of course, meaning my grandson) he is way out of control could this be contributing to his bad behavior during the day?