My minor son will be flying alone on an international United Airlines trip to visit relatives. What are United Airlines' policies for minors traveling internationally?

United Airlines has policies for unaccompanied minors aged 5–14 traveling internationally:
United Airlines' Unaccompanied Minor Service is required for children aged 5–14 traveling alone on international flights. Minors 15–17 can use the service if they want.
• Booking Process:
United.com allows unaccompanied minors to book tickets. Select the right traveler age group when booking.
You will specify who will drop off and pick up your child at the airport during booking. Contact United Airlines to update this information later.
• Seating:
United Airlines will assign unaccompanied minors seats within 72 hours of booking.
• Check-In:
Children traveling alone must check in at the airport ticket counter. United Airlines will check contact information, give a wristband, and prepare a travel document envelope.
• Security Methods:
For international flights, an agent will help you check in at the ticket counter.
• Boarding Flight:
Whether or not they went through security with their child, parents should stay at the airport until their flight leaves.
Unaccompanied minors usually board first, meet the pilots, and get seats.
• Procedures for arrival:
Unaccompanied minors should wait on the plane for an agent upon arrival.
United Airlines will safely deliver your child to their parent or other designated pick-up person.
• Customs Procedure:
After customs clearance, you can meet your child in the airport arrivals area.
Arrive at the airport 30 minutes before your child's arrival.
You must show identification and sign a release form at the airport to pick up your child.
• Extra Information:
Only nonstop United or United Express flights allow unaccompanied minors.
Children under five must travel with an adult over 18 to use this service.
Traveling alone without the service is an option for 15- to 17-year-olds.
The cost of the unaccompanied minor service depends on the number of children flying and whether it's roundtrip.