What you described is called an "exception", I don't think you can use health reasons, since they are extremely serious and anyone will understand if those are the reasons. So yes if that is the case then yea, there is an excuse. However they did not use health reasons as an excuse, but grad school and other people always use "too busy" as an excuse. "too busy" to me will always sound like, this project is not something I want to use anymore of my limited time for. Passion means that no matter how little time you have, you WILL do it, unless something serious is stopping you from completing it there is no excuses.
Also, I think you don't understand the situation, you are talking about something free, that is just your hobby. Whatever you choose to do is your own thing to deal with, no one will care, unless they are just a huge fan. Also you are even paying people as you said, so actually if you don't finish the work the consequences are totally on you, no one else. Your experiences are very your own type of experiences that have no issues, however with this game, they were taking money on their patreon, good thing they canceled it since they went on hiatus, however, how unfortunate for the people that did supported them for I don't know how long, maybe a few months... either way, people were investing in the "game" not just the demo. When you are taking money from people, at that point your decisions will involve other people, so it would no longer be a situation where you can just do whatever and only you will face the consequences.
Do you understand my meaning? I honestly get where you are coming from, but I think you didn't take in the fact, a lot of the games that go on hiatus like this or just don't finish, quite a few were asking for pre-order, or taking money by patreons. I supported one creator for a month, but I had to talk to them because I noticed they didn't really communicate a lot about their work, they said a lot of excuses as to why they are so busy just trying to get by in life. That is sad, and I am not trying to belittle their situation in life, but I am paying for a product, I am not going to keep paying for something that I can't even feel confident will be completed. Maybe I could if I was rich and had tons of money I could risk.
Anyway, they maybe will finish, but not sure how many people would want to support them on any other project in future. Besides fans and friends/family, in the business world regular consumers can't afford to be "understanding" and "forgiving" all the time, or we would have no money left XD Sometimes have to be harsh and judge people in business based on past actions.