Hi @happilyalive!
I think it's great that you are thinking ahead and trying to be the best caregiver you can be for your husband. It sounds like you have already been on this journey for some time...so just a little extra planning on your part.

The hospital nurses and case managers will likely go over all the things to prepare for his coming home.
I believe each hospital has similar but also different protocols for post op open heart surgery, so it's difficult to say with certainty what they will advise. And each and every person is different and will experience a different recovery.
Your husband sounds like he's been through quite a lot in his time here on the planet. The good thing about open heart surgery is they are so advanced now days compared to years gone by, that recovery's don't typically last as long as they did.
For instance, depending on how he's doing, they will get him up out of bed the first day. Movement and physical activity is really important. Being slightly impaired on one side may contribute to a more difficult time, but not impossible.
Diet is important after a big surgery like this.
Protein is important for healing.
For myself, my taster was off for the first couple of weeks and nothing tasted really good. Spicy or flavorful foods were gross to me at first. YUK!
You may want think ahead and maybe get some protein drinks.
Premiere Protein at Costco was a good choice for lack of appetite but needing protein.

A recliner may be useful for the first couple of weeks.
He won't be able to use his arm for much of anything.

Easy on/Easy off clothing.
Like t-shirts and sweat pants/joggers and slip on shoes. This just makes it easy to dress and be comfortable at the same time.

He may need a walker, which the hospital will determine. For stability in walking.

As for personality changes, I would say it is temporary. This is a big surgery. There is a lot of anxiety and fear associated with open heart surgery. For good reason. And sometimes the ICU experience can get to you.
All normal. All expected.
Again, for myself, I was so grateful to God that I survived. I felt like I'd been given a second chance at life. I was emotional about ICU at first, but being able to see how each day got better and better gave me hope and if anything, my faith grew stronger!
You need to take care of you too! Do you have family or friends or neighbors near-by that can help give you a break if you need one? I would say you are safe to leave him alone after a few days, but if you are used to watching him like a hawk, it may be hard for you to even go to the grocery store without worrying!
Do you like to read or have a hobby you enjoy that you can do while he's home? Something to get your mind off things and take a little break?