If he can handle commuting to Reserve in Newark for a few years, I think getting to the west coast will be possible. San Fran was a very junior airbus base years ago. Once the seniority list is ironed out, things will be more clear.
Not sure which regional he is at...but it's gonna be a pay cut for the first year. Not as severe as it would have been two months ago, but still a cut. Maybe break even on year two. I doubt his regional job is putting close to 16% away into his retirement.
How old is he? If he is under 45, I'd rather do the next 20 years at United than else where.