I've been leaving DD8 alone for the length of a quick trip to the store (or more likely, to daycare to pick up her brother on a day when she is home sick or something) for a couple of years. She knows both my and DH's phone numbers, and she's not particularly impulsive.
Can you think of any way that he can demonstrate responsibility that would be acceptable to you? Do you feel comfortable taking a nap or something and letting him be "in charge" around the house even though you're physically there?
