Will Solace's trauma is legit so underrated and I reckon that even Nico underestimates his trauma sometimes. Because, if you put yourself if Will's shoes, you'll understand what exactly I'm saying. He literally lost his brothers at such a young age and became the head-counselor of the Apollo Cabin, which meant that he had to take all the responsibilty, which also meant he had to take Micheal's place and I am sure that made him feel incredibly upset and sad, but of course he couldn't express himself because he had to take care of his patients and had to put their problems before his. As Will grew up, he adjusted to his role, of course, but he never really did get to talk about himself, because he was always the therapist friend and always talking about other's problems and that didn't help much. Being with Nico ( no hate to him ) meant that he was always helping Nico cope with his trauma, and sure, that's really important, but he needs to be heard out as well, because being the bright sunshine boy doesn't mean that he has absolutely nothing to deal with at all.
"statistically, he cant save everyone"
but its will solace alone in the infirmary after losing another life that he had put his all in too save. but somehow it still wasn't enough.