Pronouns and Their Antecedents

Here is an interesting tidbit:

$100M Calif. mansion has unusual sale requirement.

HILLSBOROUGH, Calif. (AP) — As if the $100 million asking price wasn't deterrent enough, the owner of a mansion for sale in a ritzy San Francisco suburb says the buyer can move in only after his death.

That is indeed a highly unusual requirement.  Why would anyone buy  a house that he could inhabit only after he was dead?  And why would he need a mansion for such necrotic tenancy?