Sched A> Med Expense Wkst, line 6 >about line 6>  "(2) medical expenses or personal care services required by a chronically ill individual as prescribed...."  Dr letter should work fine.
My mom is in an expensive assisted living place; she likes to stay in her room, so she gets no attention from staff other than at meals.  We have a helper hired to stay with her and do the daily activities mom cannot do on her own: Transfer from bed to chair; Toilet; prod her to eat and drink more; socialize, etc.  Left alone, mom would stay in bed and never get up or eat / drink.