And if that's her first trip across the world, get up and walk the aisle every hour or so. There's some kind of condition you can get if you keep mashed into a seat too long.
I think blood clots form in the legs then break lose to the lungs and kill you.
Deep vein thrombosis --https://en.wikipedia.org/wiki/Deep_vein_thrombosis
If it's on the old standby workhorse 747, which a lot of these long distance Asian flights are, I wouldn't worry too much about it being Boeing. If it is and she's able to pre-book her seat, the two back window seats are the best--two rows of two seats only each on opposite sides of the plane. Advantages are, besides not being "crowded," you will be among the first to board (after the handicapped), it's close to a stewardess station, and close to the bathroom. Be extra nice to the steward/stewardesses and they will be extra nice to you. And they won't jump your hump when you get up just to walk around a bit. That was my experience anyway.
Disadvantage, at least if it's United (I think.) You're eating vegetarian the whole trip. Unlike other airlines who on these flights offer a choice between Asian fare and Western fare with United it's a choice between a meat based meal and vegetable based. And if you're in the back row, you get what the other passengers refused. The vegetarian crap. I've never been so pissed on a flight, my whole life. I was starved.
Mine was a Northwestern flight, shortly before Delta bought them out. Was given a choice between meat and meatless, Asian or American--there will definitely be a lot of Asians on the flight (green tea or coffee).
And it seemed like every time I turned around they were bringing some snack around to nosh on between meals, sandwiches and the like.
NW Airlines was having a lot of financial problems at the time and was subject to a lot of bad reviews but all-in-all it was a fairly enjoyable flight for me. And this one stewardess really took a liking to me--kept checking to see if I wanted something to drink or a blanket etc.
They took the route Lindbergh pioneered (over the Earth instead of around it) and the views of the great white north were fascinating. I'd never seen anything like it. Just a vast expanse of snow and ice with no signs of modernity. I kept thinking should the plane crash there, I hoped I'd die in the crash 'cuz there's no way to survive for long in that place.