My opinion has always been that he serves no purpose with JAMES Proudstar around.
Even you just confused the original, JOHN Proudstar, for JAMES.
JOHN = stupid guy who died fighting Count Nefaria on a jet
JAMES = Juggernaut-level 90s X-Force tank who surpasses his brother in every meaningful way
...he has to be there somewhere because it would make no sense for the X-Men to bring everyone back from the dead except their first casualty ever.
Hopefully they find him something to do, though.