My Bipolar Dad Is Mentally Abusing My Mom.

location: Iowa USA.

Im not sure how much info is needed but Ill try my best to get it all down. My parents have been together for 21 years. They met in the military. my mom had me and my brother and got out after I turned 5. My dad got out about 2020. hes 100% disabled, he has depression, schizophrenia, bipolar and a bunch of other things. Growing up he was a scary dad but what military parent isnt. He relies on Social security (which he finally got not to long ago after applying multiple times) disability checks. (not sure how all that works)

My mom just ended her own business not even a year ago to take care of my grandma with cancer. so she also relies on my dad's money to keep them all afloat. My little brother, who has autism and we are pretty sure bipolar, lives with them. I moved out not to long ago.

This year my mom finally asked for a divorce. she realized the past 20 years were awful. My dad somewhat agreed and they went to a lawyer together to see what they could do.

My dad has good days and bad days. Somedays hes more compliant and agrees with mom. Others he goes completely ballistic and does awful shit. he never physically abuses but its scary. He mentally fucks with my mom. Hes hidden her wallet and suddenly "found it" and tried to act like a hero. My mom "lost" her keys and my dad went to go check the car and he suddenly "found them" halfway under the fucking car. Hes making incredibly rude comments about her clothing, body and everything else. He just recently got back from a VA hospital ward and hes acting so weird. I cant really explain it but my mom doesnt feel safe. My dad also has suicidal and homicidal ideations and has TOLD my mom how hed kill her or kill the family or himself if he wanted.

I dont think my dad would ever do anything, but recently how hes acting i have no clue. We have pets at home and hes been neglecting them so badly im trying to convince the family to find another home for them.

Also since hes gotten back from the ward, hes been saying he doesnt want a divorce anymore. Even if my mom DID have the money for a lawyer, my dad said hed "run her through". try and take my brother and everything that my mom has. She has to move in with my grandma soon and says if that happens he could claim she "abandoned" the house.

basically: My mentally ill dad mentally abuses and gaslights my mom and she cant leave. None of us, including my mom, wants my dad in trouble. But how can I get my mom out?

there's still so much im probably missing but ill answer questions. thank you.