Show him the invnentory build on bubbletracking.blogspot.com. Also look at the equation on patrick.net housing crash page;

“There are great tax advantages to owning.”
FALSE. It is now far cheaper to rent a house in the San Francisco Bay Area than it is to own that same house, even with the deductibility of mortgage interest figured in. It is possible to rent a good house for $1800/month. That same house would cost about $700,000. Assume 6% interest we can see that a buyer loses at least $4,936 per month by buying. Renting is a loss of course, but buying is a much bigger loss.
Renting:
Rent: $1,800
———————-
Monthly Loss: $1,800

Buying:
Property Tax: $486 ($729 per month at 1.25% before deduction, $486 lost after deduction.)
Interest: $2,333 ($3500 per month at 6% before deduction, $2333 lost after deduction.)
Other Costs: $450 (Insurance, maintenance, long commute, etc.)
Principal loss: $1,667 (Modest 3% yearly loss on $700,000. Reality will be much worse.)
———————-
Monthly Loss: $4,936

This is obviously for the Bay Area and interest rates are actually higher now. But do this equation before purchasing. Right now with inventory building home prices flattening and beginning to fall the finacial cost of owning is throwing away money. I am in your shoes and this data helps greatly.