My mother was abusive as hell. I can't count the different types of implements she hit me with as a kid. She punched me in the face during an argument when I was......20.

I cut her off about 6 years later and never spoke with her again. She reached out a gazillon times after a cancer diagnosis when I was 44. I ignored all of it and she died alone in the hospital.

Be nice to your kids, folks.

OP, I have cared for some pretty abusive family members, but I also declined to care for one who was shockingly violent. I don’t think you have any obligation here.

Also the PP who is likening birth moms to abusive parents, that’s really messed up. Giving up a baby is difficult and the circumstances of the birth mom are often painful.

Run!

My Dad left my mom and me and 3 other siblings when I was 10, for another woman. He proceeded to have 3 more kids with her and was very uninvolved in our lives and new wife didn't make it easy either. He tried to get out of paying child support as much as he could.
He's now 79. I talk to him on the phone about 6 times a year. I will not lift one finger or one dime to pay for any of his elder care.