He needs to be definitively converted to reliever, whatever the role, or not. But you could get someone better - if only because they're already used to the bullpen - for the same money or less. And he's still the best option for 6th starter probably - but that means inconsistent/unreliable reliever usage in the meantime.
The Athletic article the other day called him the fourth starter, and that's not necessarily wrong either... until Howard shows otherwise (health, fitness, performance). Really they should be a tandem, as Howard is either going to make a lot of 4-5 inning starts or be shut down come August.
I think the Phillies will still get their closer or at least a proven veteran late-inning arm at a decent price. It's also extremely possible that Hector is the closer, since people who believe in closers tend to value closing experience as much as, if not more than, results.