I'd like to revisit this topic and get a bit of advice. I've been considering getting into BJJ with my 16 year old son at a family oriented club with good credentials. It be a great complement to my other MA experience in WC and Escrima. And maybe it would get my kid off the dang videogames. But my friends tell me I'm crazy. I'm 59 and have some joint issues including limited movement in my ankles and knees as well as herneated/bulging discs in my back (L-5, S-1).
The back pain and sciatica comes and goes these days, but after repeated injuries and surgeries, my knees won't bend enough for me to squat down and sit on my heels, much less go into full seiza posture, and they always ache some if I bother to pay attention.
In other words I can probably about do this (without the support shown):
But there's no way I can do this (or hunker-down and sit on one heel like I've seen people do in many BJJ techniques) :
In spite of these issues I can still work my Escrima and WC effecively. I just try to be careful.
So could I also try BJJ and get anything meaningful and functional out of it, or is it strictly and art for athletic youngsters under 50???
In my opinion, you could certainly train BJJ safely and get some functional skill out of it. Your WC could even help,due to your understanding of structure and sensitivity. The catch is, you need the right teacher and the right training partners.
if you sign up at a testosterone packed gym full of competitive meatheads, where classes consist of a couple of tournament techniques followed by an hour of rolling, you're unlikely to get any good benefit and you may get injured. You want a gym where a) you can get a foundation in the self-defense aspects of the art, b) the instructor is willing to come up with whatever technical modifications you might need for your physical limitations, and c) you can find training partners willing to do lots of drills and some light* grappling without getting all competitive.
*(that's real light grappling as opposed to "light grappling until I get the slightest bit frustrated whereupon I will spaz out and go full force")
There are gyms out there which would be a good fit for you, but I don't know what's available in your area.