Sorry about your friend. Unfortunately, Bungie cannot transfer founder role to someone else. Only the founders account can promote someone else to bd founder. Furthermore, only the founder (or an admin...if clan settings permitted) can change the clan’s name. If none of these are viable options, then your only other option is to start a new clan with a name similar to the one you’d like.

Nothing can be done seeing as Bungie doesn't work with clans.