bulk prepmeals in food containers he can easily warm up 

for bulk, per container:
250gr white basmati rice (sticky, not wet, not dry)
175gr meat or fish, cook w fat or grill
100gr veggies (broccoli, paprika, carrots whatever)

variate w different herbs and spices for meat and veggies unless he's ok w eating the same everytime ofc

450/500gr food total per container
he needs 2/3 containers per day at min to start fr, esp if he is already losing weight now

these prepmeals i used to prepare for bulkers.. these guys ate like 4 containers per day next to shakes and other stuff