Why do you feel that your 14-year-old is unqualified? Maybe we have
different definitions of "qualified to stand watch" but I'd rely on my
12-year-old daughter under these circumstances. Maybe this is the
universe giving him an opportunity to show you he's more responsible
than you think? I know I tend to underestimate my kids 'cause I think
of them as having been newborns about 5 minutes ago. They're often
capable of so much more than I give them credit for.

I say, give him the opportunity to show his mettle. It'll be a great
bonding and growth experience for both of you!