Originally Posted by NoStressHere
Leave the miles in his account and have him "give" you tickets when you need them. And, yes you could transfer the miles when he passes, or you could just keep using his account.
why pay all those gift/transfer costs?
Make sure you have his PIN number, and you can complete these transactions effortlessly on your own. Also, check periodically to make sure his account isn't becoming dormant (after 3 years with no qualifying activity, the miles will disappear. Don't let that happen. Do a search here to see what Delta considers "qualifying" activity.)