I personally switched jobs, from 1 Teamster job to another.
From my own experience : No, none of the above !
Every company has thier own bargaining contract, and he might even change locals.
I basically kept my old pension, andd it's in a whole different local and account.
I can withdraw from it at age 55 and on.
I was a few months short with UPS to be vested into a new temsters pension fund, but it would have went seperatly into a new one.
The only benefit he'll get , is that he won't need to pay union intuition fees.
I guess he can be proud to be a long term teamster, but it comes with no additional bennies (no job seniorty).
401K, I have no clue, since I'm Canadian, but would think it's transferable, or he can simply start up a new one, too.