I am a trans tech person who strongly suspects this person will transition based on pattern recognition of other software people I’ve known transitioning.
I think you should think about it in terms of how much “naive optimism” you want to foster in your friends.
In truth, there’s good reasons do doubt every project, even the ones that end up being highly succesfull.
Unfortunately, it seems like human beings are highly pulled towards either working on something with unrealistic confidence, or sitting on the the couch and watching netflix.
Working on something with unrealistic confidence, even if that project itself is completely doomed to failure, is probably better for you than watching Netflix.
The one exception is, there is a higher than average probability that startup people with naive optimism end up getting into a position where they decide to end their life.
It seems ridiculous to me to float this as something that is going to happen.