Suggestion -
xxx
Get a
transparent plastic pouch (good quality) hanging around his neck.
Containing air ticket, passport, and list of phones to call (DEP + ARR points).
With my airline, parents of UM can go inside airplane, for departure.
And be at the gate for arrival. With LHR security... Probably not...???
xxx
Flight attendants know what to do with Junior Expert Travellers...
Often had some on my plane. They often came to help me fly the plane.
I do not think you object that I disregarded "access to cockpit" rules.
Then, when tired to tell me where to turn to, they go to galley to help.
I am certain one flight attendant will "adopt" him for the flight.
They often have toys or treats for kids, i.e. model plane...
xxx
No interline - right. Either Singapore or Los Angeles are fine for stopover.
Generally a station assistant will remain with him the whole stopover time.
Have a good trip, and no worries.
xxx
Happy contrails