If you are booked in the lake view room, i'd request a high floor. This is so that you can get great views. You might even be able to see the other theme parks off in the distance
If you are booked in a MK view room (theme park view), then i'd request a high floor as well. I'd try hard to get a high floor (even ask about it when you check in and ask to get re-assigned as high as possible). A lot of people were disappointed with their MK view room because the floor was low. A lot of people also expected to be able to see the castle from their bed/sofa. It's a MK view from the balcony. Some of them are great and you can see the castle and fireworks from your bed/sofa. Just make sure your expectations are set accordingly for this view to avoid disappointment.
If you're in a standard view room, there isn't much to request except for "inner C" or "outer C". the "C" being the shape of the BLT building itself and if you want to be inside the C or outside the C.
Some people request a 5th floor room, so that they don't have to take the elevator to get to the contemporary and the monorail. This could be lake view or MK view. There might be a standard view room or two here, but it's a small chance.
All ground floor rooms are going to be standard view, so you can't have a ground floor unless you book it as a standard view.
Depending on your dad's health needs, you can request a HA room for medical reasons. You can also request to be near the elevator for medical reasons. The HA rooms are handicap accessible rooms and have showers that you don't have to step over a ledge to get in, lower counters, etc.
One thing about BLT: There are no bad views anywhere in the building. Just some "okay/good" views and a LOT of spectacular views. Overall, BLT is a WONDERFUL resort with some really great views. I've stayed there twice so far and have completely enjoyed it every time.
