How do I tell dad that I am selling his house to pay for his nursing home care?

Yes, you do need to spend down assets. A house is exempt. It may still be best to sell it. Dad won't have any income to pay monthly costs on it such as taxes and insurance and upkeep. And MERP will have a claim on it after Dad dies. It is something you might discuss with the elder law attorney or whomever is advising you through the application process.

Do you think there is any reason that your father would need to be told about the sale?

His house will not cover his nursing home stay at $275. per day. I applied for medicaid yesterday, and have to spend down his assets to receive assistance.

My initial reaction matches geewiz's exactly! Maybe we'd change our minds if we knew more.

Is the amount you'll get from the house enough to keep him sufficiently long? Have you applied for Medicaid?

Tell us more!

More info would help but from what you wrote here, my initial reaction is "why mention it at all?" If you think it will upset him, let it go.