I think this is probably something we could improve upon.
The issue is that "assist %master.name%" is translated into "assist an enormous bear".
Instead, you could use "assist %master.alias%" which should return the alias, not the s-desc, and then expand to "assist enormous bear mamabear". Which would be parsed by the server as "assist enormous". Which may or may not work, depending on whether the bear is the lastly arrived "enormous" mob.
A general fix would be to allow lookups based on UID_CHAR+id in get_char_vis.
This again would require some moving of some of the internal plumbing.