Don't know if you have children (which may help with my suggestion) but another way to look at it is to reverse the roles.
How would you want your children to react if you were in your father's position?
I agree with the injection of humour as suggested above, honesty does not have to be brutal.
My own experience is a built in wardrobe that was christened "the leaning cupboard of Piza" by my then 8 and 10 year old sons. Treasures, and they should be buried

Good luck.
Andy