Re: Winter is killing my Dwarf Cavendish, please help!
Now I see pictures. The plant seems fine to me. You just did separate a pup which was too small, and in the process you did stress the plant a bit. Ideally you want to separate pups that already have some roots. Pups don't take much energy from the mother plant, bananas actually do like to have some pups.
Since your mother plant is so small, it shouldn't have any big issue surviving the winter. Just keep in a reasonably warm a luminous environment. I have noticed that smaller plant do take better the indoor growing.
But stop performing anything stressfull till spring. Just water and let it grow.