Just found out my estranged brother is dying and i really dont know how to react

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I am gonna try and keep this is brief as possible. I dont speak to my Mum or Brother and its been like this for approximately 1 year. My sister and I are close, she hasnt seen them in 10 years. My mum is a narcissist. She spread a rumour about how my daughter supposedly wasnt my husbands (not true) and ripped me off $160k. Shes an evil bitch and told me she wished she aborted me. I am currently going through the Supreme Court to have the house sold i co signed with her so she wasnt homeless and she decided to rent it out without my permission and make a huge profit on it and not pay the mortgage so now theyre chasing me and shes living it up. Its a mess. Lawyers etc right now. She sent my kids a xmas present in the mail last week and idk if it was her trying to be nice or a big fuck you but knowing the person she is i think it was the latter. Now, my brother lives with her. He has an eating disorder hes had since he was 3 year old and hes now 21. Mum allowed him to live on a diet of hot chips (fries) daily and when i tried getting him admitted to the eating disorders clinic she was sneaking in his chips for him and it was a total waste of time. Hes a little prick, he hates my husband and has said and done some pretty unforgiveable things. He wished death upon my MIL who has fought cancer... hes just a little asshole. Now anyway, i casually checked his facebook because its xmas and idk curious i guess... and he has photos of his arms looking distorted.. they look broken. theyre wrinkled, hes lost so much weight, his veins are super visible, his eyes bulging and hes so yellow. He told fb friends he has been diagnosed with liver disease among other issues due to the eating disorder and has been told this was his last xmas and hes very very ill, likely to die. Now i am torn. Do i approach my Mum and brother, who have hurt me SO BADLY in such an awful way, fucked my life up till the point i cut them off and now im happy or do i not worry about it? i worry about regret. i worry if i reach out ill regret it and i worry if i dont i will regret it. i keep reminding myself he is my dads son too and i love and miss my poor dad so much he died 6 years ago. but hes such a toxic prick my brother is. what do i do? my husband and his family do not support me contacting them and neither does my sister. she said theyve done it to themselves... its true but maybe im too nice? im torn!