Big age gap, autistic and pregnant

My friend is very mildly on the spectrum for autism mainly affecting her vulnerability, financially, emotionally etc. Also overweight and living away from family and friends.

Met a man on a dating app who is 66yrs old and she is mid twenties. Started trying for a baby and is pregnant now, 1yr half years later.

They are engaged. Her Parents love him. He has got older children who do not accept the relationship.

At first I was very taken aback by everything and called her parents to voice my concerns. They assured me everything was fine and appreciated my concern and honestly I'd never do that with any of my other friends usually.

So, I decided to just remain non judgemental and be there for support. She has been leaning on me for pregnancy support so far.

I am struggling though. Knowing her and the situation and how hard having children is. I want to be happy for her but there is something at the pit of my stomach not fully letting me.

My worries are that in a few years she could be caring for him, the child and two dogs.

What man of 66 puts an age limit in the twenties on the dating app ?

Is she just accepting an older man to love her because she is very overweight and can't find anyone serious? Why would an older man start a family again so late in life?

All these questions go round in my head and I know it isn't any of my business but I genuinely care about her welfare.

I'd love to hear some positive things to be honest and I know at the end of the day it's nothing to do with me, but I also know her very well too.