Biggles, as I understand ship's stability it is concerned with three parameters only. Centre of Bouyancy, Centre of Mass and Metacentre.
A vessel capsises at a certain angle of heel determined by the relationship of those parameters and no others. It is a simple system of mechanical moments. Wind cannot change any of those as they are all physical characteristics if the vessel - so as load is part of the vessel's mass it certainly features.
Wind may well cause the heel, but it can't affect the angle at which the system becomes unstable and falls over which is what stability is concerned with.