Unless he's got serious medical issues he can get back in shape. I'm ten years older and do a lot of physical work, construction, trail clearing...
I thinks it's stupid when people say "I'm too old to be doing this anymore," even at 30 sometimes! I think they are programming themselves to be incapacitated. Yes, our bodies lose strength, speed, and stamina with age but there's no need to hurry it along with autosuggestion.
New Hampshire and Ecuador.