you have several choices
POR - AB section - there is a room that will do 5. However only one restrooms and for 3 adults it would be crowded.
value - I like Pop - 2 rooms.
fw cabins - again 1 bathroom - but it definitely has the room - you and your kids could get the bedroom - queen (might be double) and bunk beds. in the livingroom is a murphy bed (double) for your brother. the good thing about FW cabins is they come with a full kitchen. Plus your kids can run wild here. No one will tell them to be quiet.
All Star Music Suites - has a queen bed in the bedroom, and 1 chair and 1 loveseat - sleeper types - it also sleeps 6 has 2 bathrooms, plus only a kitchennett.
finally there is a 2-bedroom at a DVC resort. this is probably the most expensive choice. but it has the most stuff. a king bed in the master, either 2 queens or 1 queen and a sleeper sofa in the second bedroom, a queen size sleeper sofa in the livingroom. the kitchen is complete with everything you need. there is a washer/dryer in the room. the master bathroom has a whirlpool tub and a shower stall. this sleeps 8.
that say - now there is another choice - the 1-bedroom at AKV will sleep 5.
also expensive are the suites - WL, Polyn, Cont, GF, BC, YC, BWI - will sleep 5 or 6.
you could still stay at WL - either in a suite, 2 rooms, or VWL in a 2-bedroom.
