My sister [35F] is leaving her husband and is upset. I want to help, but I am autistic. What things should I [28M] try to do to help her feel better?

I'm also a hikikomori/agoraphobic/social recluse, which makes things harder.
She's staying with me and our parents with her two sons at the moment. [8M] and [4M].
She was with her husband [38M] for about 19 years, and they got married about 10 years ago.
No-one's told me the details on why she's leaving him, but she's told our parents. They understand these things more, I think, and would give way better advice than I could since I haven't had a girlfriend before.
All I know is that 'He did something silly' and that they've struggled in their marriage for the past few months.
Today I made pasta as dinner for me and her. I've also looked after her kids at points in the past two days!
I'm not sure if her kids have been told what's going on, but the oldest one isn't stupid and must know something isn't right.
I guess I am asking for general advice on how to help, but how I should react to things. I am sad because I have known him most of my life, and we regularly have spoken about computer games we've been playing. Does this mean I should remove him as a friend on PlayStation Network?
How should I help my sister in ways I probably haven't thought of?
Thanks a lot to anyone who read this!
tl;dr I'm autistic and want to know the things I can do to help my divorcing sister.

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edit: I've also been talking to her about her interests and asking questions about them. People like that and she gets happy talking to me about them!


Source.