He's overweight and out of shape, of course he will prob have some unusual pain. Also, the leg press is pretty good at increasing blood pressure. Your blood pressure will change a little during exercise anyway.
If you want to test it out, and if you have a blood pressure machine on location (I lift at a gym, so they all have those machines by the locker rooms) then test it before and during exercise. If the second (diastolic) number increases/decreases more than 5 or so then it could be an issue. Depends on the machine as well, though.
Tell him to lay off any stims, too, those wont help. Ginseng, caffeine, etc. His blood pressure will prob go down if he reduces some salt, but the little water bloat you get from it is something I would rather keep. Hope that helps.