Cutting back on the water is a good thing. You want to water when the top inch of soil is very dry, provided that it's not a rather deep pot. Cut off anything that does not have green on it, including, cutting down the stems if you have to until you see no brown on the plant. Give it some time. Once garbage season is over(winter), then you can put the banana outside where it will love the sunlight and warmth.

Do you have a warmer sunny room you can move it to? maybe you could get it growing again.

i am also haveing this problem i cut back my indoor potted dwarf musa cavendish and only the very middle of the main stem is green all other rings are a pale cream colour and the top turned black within a few minites i now cant see any green i cut it back again and the same thing happened. is there any hope for this pant it has one pup that is now also going black and its one leaf fell off please help