He has kidney problems, if he died because of that, likely we'd not know until the body was hidden, after which Al-Queda might eventually make an announcement.
If he was captured/killed by military action, obviously a political boost, but sadly it would likely make little practical difference.
Al-Queda is a very loose grouping of like minded organisations, some with greater links to OBL
than others, all of which act almost autonomously.
If military action did get him, likely that Al-Queda would try all the harder to stage a spectacular, not they are not trying now, but priorities might change, for instance they have been working hard to forge links and stage attacks in SE
Asia, as we've seen in Bali as well as foiled attempts elsewhere in the region.