One day, a friend told me about how a founder he knew had raised a round, and I said something like "damn, it's always everyone else" and my friend went "why not just be happy for them? It's not like they're hurting you".
That's when I realized that yes, I could just be happy for them, and that they indeed didn't hurt me, and that I could just be making this an overall happier event by being happy.
Since then, I'm genuinely happy when anyone wins, to the point where I'll complain to people about something that happens to me, they'll say "well if it makes you feel better, that happened to me too", and my response is "why would it make me feel better that my friend also had this bad thing happen to them?", which gets some puzzled "you're right" responses.
I think it is widespread that people feel like this, hence the "if it makes you feel better" response. I think if your friend understands that this isn't a great way to feel, it'll all be OK.