My friend passed away

About a month ago my friend passed away he got me into wow originally. I want to name some of my Battle pets after his characters so he can keep traveling with me is there any way to figure out his characters names? Or are they gone forever, I remember a few but not all of them.

what loot did he drop?

nah sadly theres nothing a player can do to detect another players character names much less anything relating to an account that is not owned by them in any way, nor will blizzard because of privacy reasons unless potentially the sets of accounts are Parent > child. but even then the chances are limited.

to rename a battle pet open your pet journal UI and right click an owned pet then click rename.

certain limitations will happen at this point as certain names cant be used such as those that would tip off the mature language filters or names otherwise reserved list, along with spaces between them or _'s