Even this ancient version of Holmes beats Cockell. Cockell couldn't even make it as a Holmes sparring partner
Somehow, the Holmes of the Butterbean fight was actually capable of fighting. Was still a solid B-level fighter despite Father Time being like “dude, sit down, wtf are you doing, your GRANDKIDS are ringside”. I’d bet on him taking out a fat euro level light heavy.
Don would more than likely lose to even this version of Holmes. I really think at that point, Holmes could have maybe lasted the distance or at least gone a few good round with the some of the top guys. His experience and chin would have seen him through some rocky weather..