Shigeru, respects! I hope your family's health becomes good and the best very soon.
I have played instruments like this (same model, at least) and its larger cousin the SK7. They are indeed very good. If someone was going to give me a gift and offered me a Steinway C, a Fazioli F 228 and a SK7, I would take the SK7 without doubt.
That being said, I imagine you understand the market for your instrument is very limited, used as it is. A person discerning enough to understand how good your piano is, is also likely to understand very well that one can buy three really good pianos larger than the SK6 for the money you just described.
If you really mean to part with the instrument (probably you don't), I think you will have to price it at less than half of what you just said. Otherwise, why would anyone seriously consider getting this instead of, say, an August Forster or a Mason (depending on taste), which you can get new for a fraction of $65K? When you get to that amount, you can get a Bluthner Model II or a Steingraeber C-212; a matter of taste, of course, but at least for me at that point the SK6 would just get a smile of appreciation and a kind "see you later."
I wish for you that you can continue to enjoy the instrument, and that you turn out not to have to part with it.