Custody Of Dog Abandoned By My Parent In Location: Massachusetts

Location: Massachusetts

Hi All. I have a parent who's been an alcoholic for my 40+ years. They have been section 35'd (involuntary commitmentes) 3 times this year. Prior to that, they have been to private detox 8 times in 4 years. After being out of his third section for 3 1/2 weeks, 8 days ago he began drinking and I haven't seen him/talked with him/he hasn't come him since.

We have lived together for 8+ years, but I simple cannot deal with this anymore and I'm moving out. We have a 9 year old rescue dog that I've been the primary caregiver of for basically 4 years now (he hasn't been able to stay sober for longer than a month at this point) because when he drinks he neglects the dog (doesn't feed him, let him out, mold in his dishes, etc.). Not only can my parent not stay sober enough to be a competent owner, but my dog also needed surgery that my parent hasn't booked because of neglect. I'm hoping to make an appointment this week.

Because we got the dog when I was a teenager, all of the paperwork is in my parents name. They took care of him for the first four years, but have been deteriorating quickly over the last four. I'm hoping if the vet lets me book the surgery it will show that I can pay for his care despite the fact I've been taking care of him for years. I know there is a way to petition for custody of the dog after filing a restraining order, but I'm hoping not to do that. I love my parent, I just have done everything in my power to help them get better and they don't want the help. I feel like on paper I have a bad case, any advice?

TL;DR my alcoholic parent who has been in three 45-day involuntary holds this year (4 total, 1 from 14ish years ago) and has been rapidly deteriorating and neglecting our family dog. I'm moving out and despite the fact he's on paper (via vet bills) seems like the primary caretaker, i have been taking care of everything over the past 4 years. i ideally don't want to file a restraining order, would i have any hope in a small claims court? what should i do?