I have heard of gardeners in the North overwintering tropical Hibs in the basement. It sounds like yours want to sleep over winter. I think it may bloom better next season if given a rest. You can also trim it back.
Leaves can drop when not enough light. Hibs loves the sun. Also a house is stagnant compared to the outside.
I grow the hardy Hibs. The information above is from what I have read.
