At http://chat.stackexchange.com/users/3786, the "parent user" link links to a user page on a dead site, and that URL redirects to the Area 51 proposal page for that site. Is there a way to see this chat user's user page on another site or Stack Exchange instead?
I think this is currently not possible. Regular moderators cannot assign a different parent site for these users, because the UI for that is broken.
What should happen when a chat user has a closed beta as parent site: Assign Area51 as new parent site automatically. I couldn’t find this user on Area51, he might use another name there.