Is Calling Adult Protective Services My Only Option?

my mother and brother are both autistic with intellectual disabilities and they've lived together the entire time my brother has been alive. when i was younger, i figured all of the adults in my life knew to step in when things get off-the-wall and out of control. i've now been humbled by this as a 30-something year old. my mom was extremely abusive to me when i was a young child so i know that my brother probably experiences this too, and has for his entire life.

now that i know things can change and that there are resources, i'm still stuck in knowing what to do in this situation. last week, my brother walked out on my mom and slept outside in a park somewhere for the whole week. when my mom didn't hear from him at around the 24-hour mark, she contacted me and told me as if it was no big deal. absolutely enraging. he is also a neurotypical-presenting Black man, so if things ever got weird with the cops, we all know what would happen to him. i cannot bear to even think about it.

after not hearing from my mom for a bit, i tried to find every resource i could to see if anyone besides the cops could find him, to no avail. i filed a missing person's report. turns out he was in the hospital fighting off a severe sinus infection. he's back home now with my mom. this is the first time he's ever really done something like this, like it was his final straw. it sounds like he had come to the realization that my mom is a poor caregiver, and that he wasn't taught any of the things that he should've been learning his entire life. he sounds resentful and like he's experiencing suicidal ideations.

my mom refuses to acknowledge that both herself and my brother are neurodivergent. she both protects him from everyone else and harms him by doing so. she refuses to get him any sort of help, whether that's psychotherapy, inpatient care, independent living facilities, literally anything but him sleeping on her floor in the room that she rents out. my brother has never had a job at 27 years old and she refuses to get him help with that outside of "just apply" in the state of this job market.

do i have any choices here besides calling adult protective services? what can i do as an outsider who lives out of town from my family? he so clearly needs help and i want to do something before it's too late. my brother is also rigid in his thinking so it's impossible to get through to either of them how serious this is. does anyone have resources to help with these kinda of situations? i'm in the U.S., Maryland, and my mom and brother are in Prince George's County. TIA