I'd have to agree with cyclehen , B-ball would have me a basket case for a week! 1/2 hour of B-ball would totally cripple me... if you're not accustomed to the movements, it can real hurt and even cause injury.
Brendan, you don't mention how young you are, but for anyone at 63 things come a little slower than they did 2 decades prior. Even the most fit and fantastic 60's athletes give defference to dealing with the age thing.
If he hasn;t had much of a consistent exercise program before this, work on building up, and certainly for longer than it might take a younger person to increase fitness.
Not saying to 'go easy' necessarily, but do things which build and support the overall body structure.
Not only does one have to consider muscle condition; but the structural strength is essential to be judged, relative to what is possible at this time. Not just bone, but most importantly, connective tissue. Over-stressing connective tissue (as a 1/2 hr session of B-ball might) could cause lasting injury which some people can never recover from. Certainly you don't want to put him out of action for a couple of months and lose what ever gains he's already made.
Yoga as mentioned, especially slow-flow or therapeutic (or if more easily available - Pilates), and a well thought out weight program would provide a strong base from which other activities (like B-ball) can then be incorporated.
Aquatics are good base conditioning athletics. Structured 'programs' with a knowledgeable instructor would be great, cause if they're really good, they're paying attention to how their 'students' are perfoming and can spot poor or potential injury causing techniques.
Then there's the consideration of his current 'challenges'. Not knowing what a fused hip is, it does sound like it needs some serious consideration. 'Core' work really helps deal with back issues, again Yoga and Pilates can really help here.
Depending on the hip issues, if he's able, a 'spinning' class/program would do great things for his aerobic development and possibly also be of some therapeutic value for the hip (again, really depends on what those issues are...)
Old machinery needs to be well warmed up and more frequently lubed. It just takes a bit longer to get a head of steam...
and maybe he needs activities which just aren;t on your current radar...