I don't know the history with hubby but if my husband had done this I would be pretty upset.
If you want to stay married then you have to decide how to handle this.
If this was my hubby I know what I would be thinking. I would figure he panicked knowing I was coming to town and he better have something to show for his time and effort in house hunting. I admit I have become quite gripy since going through menopause.
The point is, I guess, that you can live in a tent if you have too. You can live in a mansion too. I think that letting hubby know you are a good sport is okay too.
I know I would be pissed he didn't wait for me. BUT, it would not be worth my marriage to get all pissy and hold a grudge.
Here's what I would do to make it through this year. I would get to know the land lord. If he is an easy going sort of person I would find out if you can get out of the lease early. Hint that you have found a home you'd like to buy but are worried about his lease. If he says it's okay then you guys could start looking for a home to buy pretty soon.
If not then you are going to have to make do for a year. That last 3-4 months you need to be pounding the pavement looking for the perfect place though.
You are going to be gone quite a bit if I'm reading this right. You are going to be helping this family member through a very difficult time. So, perhaps you can make do with the living arrangements at home easier since you won't be there every day all day.