Just saw this. Once, many, many years ago I did a trip to Sydney which was basically fly over, there for 3 days (I think), back to UK. It nearly killed me.
I did it for work and didn't add on holiday at the end of the trip (as I would ideally have liked to do) as I was due to go on annual holiday to Mexico with my OH on my return.
Highlights of the trip were a small child crying incessantly all the way from London to Singapore - 12 hours I think - nothing to be done, just had to suck it up but that started me off with an immediate sleep deficit.
Worked for 2 days while I was in Oz, on 3rd day wanted to die but compelled to attend a bbq held by one of the senior partners - almost vomiting with tiredness.
On flight back, saw a family with 2 small children get on at Sydney - all dressed in identical white cargo pants, white t-shirt's and birkenstock's. I spoke quietly to the attendant to explain what had happened on the flight on the way over and to beg to be moved if these children made noise as i was totally losing it mentally by then. She looked shocked to see me as it turned out she'd worked on the flight on the way out. She'd never seen a passenger return from Sydney after such a short trip. She'd been on a beach in the interim as crew need to have a break before they can do the return flight - so she looked great - and mentally sound. 😳
She agreed if the kids played up she'd see what she could do but so far they seemed really well behaved - so we agreed to see how things went.
As it turned out the kids were incredibly well-behaved, no problems at all and the Dad seemed very nice, very pleased with their seats and chatting nicely to various attendants including mine. Just a nice guy.
Then suddenly the attendant came over, hissed at me "do you realise who that is??!!!"
I didn't.
It was Jason Donovan. 🤣
When I got back to London I crashed completely from tiredness, had to cancel my holiday to Mexico. I've never made it there.
However I have slept with Jason Donovan. In a sense.
As to your question, no matter how much you love your friend, think carefully about a trip like this. You may be able to afford the cost but just beware of the impact mentally and physically. Send him a lovely message or even better skype/facetime into the reception at the bit where they used to read out the telegrams - pretty easy to arrange, and memorable - and then have a lovely special meal/celebration with him and his new wife the next time you see them in person.