I'm sorry you are going through this. And I am sorry but in my honest opinion i think the next time she doed something unsafe to herself or threatens suicide or even starts going off about these bugs you should call 911 and have them come out
Tell them everything you told us
Tell them you fear she is a harm to herself and needs help right away. Hopefully they will take her in on a 24 hour hold and get to the bottom of this. It will be tough to do but if she refuses help for herself it must be done. Your brother likely has wrecked twice because his mind is preoccupied worrying about your mother. Don't have bad feelings towards her something. is very wrong here and she can't help it more than likely. I wish you the best.