A friend of mine has a strelitzia which he is worried about. It's
dropping leaves faster than it's growing new ones, is not down to one
fully open leaf and 3 other developing ones.

The existing leaves look healthy and dark green, and no sign of pests or
diseases.

The leaves which drop simply turn yellow as they might be expected to do
when they reach the end of their life.

He's keeping it in a S window in his kitchen, temperature between 16 and
19 deg F.

Is it just bedding down for the winter, or does it need attention?
--
Kay