Hi, Sassy, and welcome back. Well, I think Bobby needs to speak up if he doesn't want to do these things. If you get in the middle, there will be a lot more problems than what you are dealing with now.
My MIL lived 7 blocks from us. I loved her dearly but she was calling my husband to come over to change light bulbs! He would complain to me about it so I told him I was the wrong person to be complaining to. He needed to tell his mother that this was coming to an end. I stayed out of it. He told her and that was that. Everyone was a good terms and I wasn't blamed for anything.
So, Bobby needs to talk to her. Maybe he wants to take his brother, too. That could be happening but I wouldn't get so worked up over that.
Sherrine