Am I being insensitive to this guys trauma by not wanting to date him

I befriended someone and I know he likes me. He's a really sweet person but honestly I would not be able to be with him. He has severe trauma to the point he age regresses. Which is fine. I'm a psyche major and I know she regression is a healthy coping skill. And if it was some of the time I could totally date him. But he's age regressed about 80% of the time. I can't be in a relationship like that. I would feel more like their mom than their mate. I'm sorry I don't want to have to carry a pacifier on me 24/7 for my mate. I was honest with him that I didn't want to date but we could be friends. He seemed happy with that. We still text and he sends me snaps. I don't judge him when he's regressed. My sister however told me I'm being insensitive to the guys trauma and it's horrible that I think people like him don't deserve love. I totally believe he does but I don't think I'm the right person for him. I'm sure there is someone out there for him. Not me but someone. I think my sister is upset because she has very similar trauma to him as she was a sex trafficking victim and she has said she age regresses at times too but not all the time. I sympathize with her but for me someone who is age regressed 80% of the time is just too much. She keeps saying I'm selfish and people like me are why people like her with trauma feel alone. I don't understand why she's mad FOR him when he isn't even upset himself. I care very much about people's trauma but it doesn't mean I have to date him. Wouldn't it be more cruel for me to date him and hate the relationship and start resenting him? Wouldn't that be unfair to him?