All 3 healers have 4 button options. It's more about what content you expose your brother to. FC 4 and 8 man groups running Leveling and Main Scenario roulette every day will get his Healer to 80 quicker than you think.
Just because it's the only level 1 healer, Conjurer Whm is the ideal choice. Put a Rdm in the group have them focus the tank and avoid telegraphs. For 8 man, have a healer with experience.