I have been encoring my husband to take his mother to adult day care but she is so aggressive. He doesn't think it's fair for someone else to be burdened with her behavior and there are no other family members other than me. He is with her 24/7 and just needs a break. She has recently become aggressive with me too.
From my own experience and listening to that of others in my support group, day centers generally can't cope with clients who are aggressive.
Aggression is hard to treat, but there can be encouraging improvements in some cases. Try getting medical help.
I also kept a calendar where I would note behavior changes in my MIL. This helped the doctors and us.
I noticed that the better the routine and sense of control MIL had the better her behavior.