Just popping in with a handhold as I was in your shoes a few years back with DH, only I was at home with our newborn panicking rather than at the hospital with him.
The first few days, weeks, months will be a blur as you all adjust to the new normal. I’d strongly recommend looking at diabetes UK for any clinical trials that your DH may be eligible for. There’s such a slim window for admittance as they often need you to be within a few weeks of diagnosis, but DH was part of one for his first year and honestly the amount of help and support he received was invaluable. He also got a better CGM than he’d have had through the NHS which really helped with monitoring in the early days.
When he speaks to the doctor he should also ask about the DAFNE course. He might not be eligible just yet, but there’s often HUGE waiting lists to join so worth getting the ball rolling early.
The other thing we learnt through bitter experience was not to try to bring his HBA1C down too quickly. The hospital didn’t really give us a huge amount of guidance outside of the figures when he was admitted being “catastrophic” so we went on a full health kick, as even though he was T1, so not remotely down to diet, we’d been eating all kinds of crap whilst trying to survive the early weeks with a newborn. Long story short, DH had all kinds of nasty side effects from bringing his levels down too quickly and was later told they’d only encourage such speedy adjustments if he needed life saving surgery.
Feel free to pm me if you ever want to chat, or need someone to lean on. 2 years on DH can mostly eat what he likes, it’s well controlled (though he’s just out of the honeymoon phase now, which is coming with a few new surprises) and whilst the mental load of it does take its toll on DH, life has generally carried on as it did before.