Answer
Did you know body requires folic acis, Iron, and vitamin B12 to produce RBC. If the person is deficient in these vital nutrients then anemia is the result.
I recommend you to get him tested to know the root-cause of this dilemma.
Normally, I recommend anemics to eat more iron from red meat, chicken, and fish. And from plant sources like leafy greens, dried beans, whole-grains, and dried fruits like prunes, and dried apricots.
I would like him to include these iron rich food with vitamin C rich foods, and probiotics like yogurts, and fermented foods.
Cook his foods in iron-cast pots.
And ask him to avoid egg, caffeine, and bran completely. As it interferes with normal absorption of Iron thus lack of formation of RBCs.