he pawned it or traded it....for drugs. do NOT get him a replacement...that is one more thing for him to pawn. he didn't forget, he needed drugs. you need to fACE the harsh reality of what addicts will do for dope. could be a pawn shop or some dope dealers pocket regardless, it is GONE....collateral damage.
no more jewelry or hawkables for him. last thing YOU need honey is to be cruising pawn shops!? or spending MORE money to give him something that can be traded/bartered for drugs.
is he even IN treatment yet? you realize you are looking at a good YEAR before he gets the chance to even out and resemble a functional human right? a year of SOLID unbroken devoted recovery. working it harder than he has EVER worked anything else in his life. daily commitment. with laser like focus. go read up in the Newcomers Section and learn just how hard it is to get three days much less three weeks, months, years.