The trust terms control AND the actual title on the bonds will determine how it has to be handled. Was a probate filed? The personal representative can get authorization to cash bonds from the trust still titled in the name of the decedent if that is the problem. Hard to really understand what the actual issue is other than the change of ownership form that someone else wont sign. If the disinherited heir is on the bond as a holder, you may have no choice but to file suit to get that title cleared. Seek legal help with all your documents.
The answers given are limited to the facts as given and presumed by the answer itself. Without seeing actual written documentation or having a conference to more fully explore the issues, this short answer has only limited application. Make sure to seek legal counsel and provide all documentation to get assistance in making informed legal choices. Bstein@dcfsz.com, 305 377 1505