Platinum ring repair

This is an odd question, at least I think so. One of my fellow
jewelry shops called me today about a customers platinum wedding set.
A Platinum wedding band with a guard of platinum. The ring in between
the guard keeps bending out of shape. I told him it sounded to me like
the metal of the band had lost it’s temper somehow, to try to work
harden it or heat it and quench it to get the temper back in it. His
jeweler refuses to heat the metal, he says that platinum can not be
tempered in that way. My question is, can it be heated or is there
another way to put the temper back into the band? I think the metal
lost it’s temper when he soldered the guard to the ring. He also said
he wished I’d go ahead and work platinum, he’d send his work to me if
I would. My next question is how difficult is it to work with platinum
and what kind of a set up and price would I be looking at?..Char