Family members who care only about mom’s money and not her?

It really shouldn't matter if he is listed as co-executor.  The estate will pass through probate and he will not be able to make any decisions on his own.  If he fails to follow the rules, then he can be removed by probate court.   Honestly, there really isn't any need to bring it up to her.   How her will is currently listed, no matter who the executor is....is how it will be done.   Let them be angry and stupid.  Miserable is as miserable does.

I would not put Mom thru that. It really doesn't matter who the Executor is. When the will is probated, the Executor has to follow the rules of Probate. Sending letters to the beneficiaries saying the will is now in Probate. All debts have to be paid. You will probably need a lawyer for the accounting and closing probate. When all that is done, the assets will be distributed as Mom had it written in her will.

Are you the executor with your brother listed as the co-executor? Depending on the language, it may not matter if he is listed as that. It doesn't necessarily mean he has equal responsibility for settling your mother's estate. Many times it only means if the executor is unable to do it then the co-executor takes over. However, no one inherits anything until after she dies so anything before then still belongs to her. It could all have to be sold or spent to take care of her. One never knows! At this point in time, I would make sure someone has a DPOA and if there isn't one, that would be what I would ask her to do. I would be watching her money to make sure there is a way to pay should she need to go into skilled nursing.

Your poor mom is 96 and nearing the end of her life. She must feel like the vultures are hovering to pick her bones.