OP, have you ever flown business class? We did this year for the first time, from LA to Manchester (via Heathrow). The business class lounge at LA was amazing, so quiet and loads of seats to choose from. Did really feel exlusive, like we were in celeb-land! But it went downhill after that really, in terms of value for money. At Heathrow the lounge was shit, a glorified all inclusive type of atmosphere - overcrowded and noisy and with uncleared tables at Heathrow.
Yes, so we had lie flat seats on the plane from LA to Heathrow but it was over the engines so even with ear plugs in and it being a night flight it was just so noisy. And they turn the lights out and just expect you to go to sleep so don't expect much service at all. I was uncomfortably hot and so thirsty. With the noise too I didn't sleep a wink even though it was a night flight so I SHOULD have felt tired, so all in all, it was a total waste of money.
The food was fine but, it was just food, we'd had loads of it in the LA lounge anyway so didn't need much. And of course had availed ourselves of champagne in the lounge too so by the time they hurriedly brought us a glass of champagne as the rest of the flight was boarding it didn't feel much of a treat to be honest. I mean, it's just a glass of fizz when all is said and done!! The meal in the morning as we were approaching the UK was a cooked breakfast if you wanted it. But it was, like, 3am to our body clocks so we weren't really hungry and ended up leaving a lot of it.
Business class from Heathrow to Manchester was pointless. So we could sit at the front of the plane, get off first, and we had an empty seat between us. So what? They threw some afternoon tea at us and were virtually hovering over us waiting for us to eat our scones because the flight was so short they needed to collect the tray back in ready for landing. Hardly a premium experience. We didn't enjoy it, we'd had the lounge food at Heathrow and our appetites were all over the place.
If we were doing it again, I would book economy but look VERY carefully at the type of aircraft and choose my flight and seat accordingly. We had a very pleasant journey indeed in economy from the UK to the US and would book the exactly the same again in a heartbeat. I would be happy to pay for my DH only to go business class if he had the issues your DH has, as I really don't think business class is worth the thousands of pounds extra per family. I was glad we tried it, but unless someone else is paying I wouldn't bother with it again. Maybe if we were going to Oz or somewhere longer than 11 hours I would consider it.
What you'd need to consider is that he would be "queue jumping" if he was business class, so he'd be on his own checking in, separate from you. He'd then have access to a different lounge to you. Would he be able to manage on his own? SAme with getting off, he'd be off the plane first having to wait for you to get off.