The ArtCyclopedia site unfortunately shows:
Balthus, [French Painter, 1908-2001]
Also known as:   Count Balthasar Klossowski de Rola.

It would appear that he is no longer living.

The last significant exhibition of his work in which he participated appears to have been about 1991; and showed only his later stuff in the archived catalog, as far as I can tell. No little girls there. A couple of "poster" sites have notices about his "copyrights administered by ..." which may explain why there's so little of his stuff on the web.

John