I am closing my business after over 30 years. I have a full time employee who has been with just over 20 years. I told him 9 months ago I was closing business and he stayed on until I close this September 30th and both of us are retiring. Do I owe him severance pay. My business is a small corporation

Strictly speaking, you do owe severance and the amount can be significant. That said, if his intention is to retire, I would let it be for now. Severance is generally on my paid to those who plan on continuing to work elsewhere, not to those who will be retiring. Should the situation escalate, it is very important that you give me a call.
Lior Samfiru