I don't remember enough about hohenheim's whole situation to say anything about the other part but this is just a weak reading. he lost it for a reason and it's a meaningful conclusion to his character arc
i get that, but ed refuses to let hohenheim use even his Own Life, Willingly, to save Al. his decision to save hohenheim is ultimately pointless since he just dies a day later also Willingly. it's not like ed was forced against a wall or was using unwitting human lives like with a philosopher's stone, and even if the final souls powering hohenheim weren't his they were already explained to be just energy with no conscience due to how long he's lived.
the decision to get rid of his alchemy was ultimately a good move, since he was lead so far down the path he was because of it, but it still makes me a little sad that we were denied any potential sequel or continuation and it's revealed their entire journey could have been stopped early on if only ed realized the what the door of truth symbolized sooner