Husband's sister

My husband's mom passed away on the 26th of October. He didn't even go to the funeral and his sister has been trying to reach out because he's the only family she has left. His mom would leave them alone for days at a time and wasn't really there. His sister ended up having to raise him but she didn't do a good job. Even for her age. He said she bullied him horribly and would take food from him and make him do things for her and her friends like send him to the store by himself when he was 6 and she was like 13. She loved to call him a bitch boy and the abuse only got worse as they grew up. She forced him to dress up as a girl to entertain her friends and eventually got physically abusive and let her friends abuse him. So there's a lot of bad blood there. I do understand that parentification is abuse and neglect, but also idk I feel it's common sense to not treat someone that way. Doesn't sound like she actually raised him. Just abused him. Anyway she's been reaching out to my husband and me because she wants them to have a relationship now that their mom is dead. My husband doesn't want that. He moved away from his family and wanted it to stay that way. She's sent me some long messages about how she's sorry. I haven't responded. I was wondering if I should maybe voice my opinion on this or let my husband take the lead on how he wants to handle this and just be supportive.

Edit: The abuse started when she was 13 but continued until he left home. He left home when he turned 17 so she was 24 still being very physically and emotionally abusive towards. It wasn't just her being 13 and terrible to a 6 year old. It continued until he was in his late teens and she was well into adulthood.