We had our 8th grader take our 4th and 2nd grade siblings around Great Wolf Lodge and do Magic Quest together while DH and I went across the street (from the resort) to the outlet mall last winter. None of the kids wanted to go shopping with us, and the age to do MagicQuest alone was 14, so we (and the resort) were perfectly fine with it.
The kids had a blast - when they got tired of MagicQuest, they went to the snack bar for something to eat, then went back to our room and watched TV. Our only stipulation was that they were not allowed to go to the waterpark without us.
Based on that, I would let DS watch his siblings again at a hotel. They LOVED the freedom!