My brother in law lives with my mother in law and does help take her to the doctor but he is using her credit card for meals and charging for everything. He has had her write him checks and just withdrew $2,100 for his car that they said was repossessed. He has been on drugs before and we think he is on them again. My husband is in charge of her estate and I help pay her bills so I see all this on her bank statement. What can we do so that he doesn't spend all of her money?
Accounts should be changed so that he has no free access to them, as FF mentions.
If Mom doesn't have any type of memory problems, sadly she can spend all her money the way she wants. All you can do is lecture to her that she needs to save her money for if she needs help later down the road. Sounds like she has been your brother-in-law's ATM machine for quite some time.
Is he being paid a salary to caregive?