I dislike those kind of lopsided prescriptions because they don't teach maintenance so the only modes are draconian deprivation and SAD-as-usual.
Purely unqualified advice but:
In his shoes I would completely forget the total weight and just try to live as a person at his goal weight would. That means a weekly routine of shopping and cooking for complete nourishment--put another way, don't try to "lose 200#" or even "lose 10#" just cultivate a routine one can be proud of and reinforce permanent behaviors. IMO most obesity is at root a culture deficiency and things like refined protein shakes are just a daily reminder that he's defective--I'd rather see him rejoin the human race with our lovely soups, salads, steaks, and (small) desserts and let the energy balance shake itself out.
Lots of: urban hiking, cycling, sprinting
Lots of: fresh meat, seafood, eggs, organs, tubers, starch fruits, vegetables, meat fat, dairy fat, oil fruits
Some: cured meat, dairy protein, sweet fruits, rice, pulses, tree nuts, oil seeds
Minimal: soy, refined proteins, sugar, liquid carbohydrate, grains, refined oils, peanuts