My first patient who ever died actually died from this. Fractured his ankle playing wiffle ball of all things.
I dont believe you can self administer such a thing. There are a lot of great reference resources out there, but you need to have guides/teachers to really realize your potential.
Focus on the military basics as a framework to keep you on track: shoot, move, communicate, sustain.
Resources I've found helpful/effective:
Shoot Modern day gunslinger - Don Mann The art of the rifle - Jeff Cooper
Move Starting strength - Mark Rippetoe 5-3-1 Forever - Jim Wendover Run Strong - Kevin Beck Slow Burn - Stu Mittleman
Communicate Life experience/practice/confidence
Sustain The Ranger Medic Handbook - North American Rescue Wilderness Medicine - Paul Auerbach
I've come back again and again to this basic framework while teaching Soldiers. But, as I say, you'll be needing a teacher. Books can only take you a very limited distance. You need to get a workout partner who is more fit than you. Join a martial arts gym where the people are more advanced than you. Get a running partner who is faster than you. Enter into as many competitive shooting events as you can, against people who can outshoot you. It takes humility, but these people will be the teachers you need. Also, very importantly, volunteer in your community. That's the way you can learn the mindset/motives of a good Soldier.
Try this as a basic starting schedule: Mon: long slow run Tue: Lift Wed: Interval run Thur: Lift Fri: Long slow run Sat: Ruck Sun: Church (Spiritual health is just as important)
In addition: Roll at an MMA gym at least once a week, even if you're sore (especially if you're sore)
Shoot at least one a week, even of its just bullseye plinking (competition is better)
Read voraciously during your found time
Join a group or take a class that forces you to regularly engage in public speaking
Volunteer in your community, I cant stress this enough
The only way to actually learn the lingo, the customs and courtesies, and the drill and ceremony is to join. But, if you have the initiative, you can hammer yourself into a respectable warrior with help from the people you meet along your way. Also, you're guaranteed to meet a lot of pedes in real life while you're at it.
Sources: I was the Medical Platoon Sergeant in a Light Infantry Battalion
Would likely be looking for DVT/PE. Especially with as old as he is.