No one is able to do much of anything they want then.
Maybe I shouldn't focus on this one line, but do the other characters really
only want to commit violence? Could it be that the rest of the table is pushing for physical conflict when it's not necessary at all, and the Solace really does want to explore better ways to solve problems? That's kinda scary, right there, and maybe the player chose that playbook because they didn't want to just see bloodbath after bloodbath and wanted to explore something besides fights.
Anyway, assuming that is
not the case, why are these other characters bringing around the Solace when they head out to do their dirty work? And why is the Solace preventing every single fight? Is there really nothing worth fighting for in this apocalypse? We've got slavers and madmen and flat-out mutants in the wastes that are hurting people when the Solace isn't around.
Maybe show the Solace what happens after the groups disperse: the pent-up anger gets taken out on the weak elsewhere. Show them that this move isn't an "I win" button, it's just forestalling violence and putting it off-screen, where no one can prevent it.
Also, definitely talk to the other PCs about this. I seriously don't understand why they're hanging out with a psychic pacifist when they want to crack skulls. In my games, the PCs are almost never entirely present in every scene: they're always off pursuing their own agendas and sometimes coming together when those agendas coincide. Remind your other players that violence isn't off the table, it's around the corner... where the Solace can't see them. Hell, plant that seed in their mind that maybe they're better off without the Solace after all... could lead to some good drama at the table.
Have they talked about it amongst themselves?