Wheelchair passengers eat in their rooms or at their seats, so this shouldn't be a problem for you either as "room service" is an advertised perk of having a sleeper. As I am a wheelchair passenger, we simply told our SCA around what time we wanted to place our order (like 6:15) and he came with a menu he checks off as he tabulates your meal. He can write down special requests as well. Make sure you ask for condiments, like salt, pepper, steak sauce, ketchup, etc. We usually had our meal in 20 to 30 minutes.
Three of the four SCAs came back with the food served on a tray, using cloth napkins as a makeshift tablecloth. The other SCA packed the food into a TO GO bag. The bag was actually just as nice as we had a place to toss all our dirty dishes and trash.