I would get him to educate himself on adhd. There are many sites. Additude is a great online support for both spouse and adhd person. I would also read up on it as much as you can so you can understand his condition.
If he's on Instagram I highly recommend Matt Raekelboom and the life actuator.
Matt has personally helped me in so many ways with his short but easy to take in videos. He owns journey2adhd whichnis really helpful. He gives all sorts of tips.
I highly recommend your husband uses his phone calendar as a reminder tool with lots of alarms and notes put in about what he needs to remember.
Also have a chore chart or reminder chart that is magnetic and can go onto the fridge. This is can be a list for him to check for what he needs to do that day. Get him to write the list himself and set reminders on his phone to look at it.
With the the time blindness, he needs to give himself an hour longer than it should take for whatever needs to be done or wherever he needs to be.
Anything that needs to be remembered to take out with him, put it near his shoes so he won't forget things.
Get him to remember to check in with hinself all day. Had he remembered to eat, drink plenty of water, exercise, has he had enough sleep?
Dopamine is what we need to concentrate, motivate us and help us focus. To feed the Dopamine, tell him to use music or anything else he finds interesting like a podcast. It helps me to stay focused on task when something.else is feeding my brain.
Just a side note, he's probably masking all day at work and when we do that, all our energy goes into it so we are literally exhausted by the time we get home.
Sometimes when I'm overwhelmed after work, I have to lay byself in bed for 20 mins just to come around when I get home.
I hope you don't mind an adhd person advising you but neurotypical people don't always get why we do what we do. It is managable and it can be done. It takes education, time, patience and practice. I am also unmedicated.
I aren't terrific with chores but I am trying to get better with a lot of the things I've listed. I've only realised I had it in the last 2 years and I'm female. I know we are maddening but once he works out how to manage his condition, it does get easier.
Good luck to you both.