Your guy (or guyette) should remove (via sandblast, grinder, or other) all
the rust down to bright metal, and apply the best damn paint he can get--a
TNEMEC epoxy primer and 1 or 2 finish coats is probably going to be the best,
but a pain in the ass to work with.  I would disassemble to splitting
woodwork (it'll continue to split with the rusting steel/iron inside it and
continuing to rust and force the wood to split), conserve it, and reinstall
the whole works.

Rotsa Ruck.

Ralph