Well, there are children involved. So, I wouldn’t know how to advise you on that. But I believe in general in family bonds. I still think your brother has mental health problems and the army is going to exasperate that, probably will come back with PTSD. So, likely he’ll come back in your mother’s life more than likely more angry and more wounded.
So, I don’t know if you are married but if you feel for the growth and safety of your children to get away from the situation than do it. I would just allow Mom as somehow involved and aware through phone calls and pictures.
Again, my family is not punitive and I’m grateful. I’m learning so much on here of different ways Catholics practice and it’s eye opening. I’m just grateful I was raised where I was raised with the Catholic community I am with, with my family being as they are. Maybe read the Beatitudes, “blessed are those who suffer for righteousness sake.”
The world isn’t win lose survival of the fittest. At least not where I am. Generally, in my part of the world your brother would be known to be suffering from mental health issues. I’m not going to diagnose but sounds bipolar. Either way, always love your mother and in some way keep her involved. I cut out bad people and influences in my life or don’t include them anyway. But your mom sounds like a woman who has gone through much suffering. I can see why she tolerates your brother so much. Even if it is unhealthy.