LOLOL......That's funny! I would write my son back:
Dear John,
Your mother and I hope you and whats-her-name will be very happy. Also we are hoping your marijuana farm prospers, as your mother and I will need extended care in our older years and are expecting you to provide for it. I'm sure we will be needing a place to stay (with you all of course!) and help with our daily needs, such as diaper changing, teeth cleaning, etc.
Love,
Dad
HAHAHAHA....see where honesty about a report card could have spared you this harrowing thought?