No. Not really.

If you delete the user first, then the "pointers" to the custom view and the custom view itself are whacked.

If you are good with Tableau Server system table Kung Fu, you could (not supported, somewhat risky) change the "creator_id" value of the custom view inside the customized_views table to someone else, but you'd have to have the foresight to do so before the original user is removed...