TPQ is British.
@The Pentacle Queen - at least in the US, they have to spend down their $$ in order to get aid, and the system looks back a few years to make sure the money isn't being socked away in the Cayman Islands or anything.
Talk to your parents and bring in their solicitor. Your folks are competent so these are, currently, their decisions, but talk to them about your concerns. If they don't have a will, urge them to make one (hence the solicitor) or update theirs if it is more than 5 years old. Ask them to consider their future care situation and a few scenarios.
I think you are thinking - and a lot of folks fall into this trap - that the whole thing is all or nothing. They are in their current home or it's full-time care. But there are several stages in between. These depend on your parents' health and what it is down the road.
For example, your parents may be otherwise healthy and perfectly competent but have mobility issues and may need a place with one story but not much else, and that might work for them for a while. Or they might get cancer and require treatment but remain with it mentally and just need help during chemo. Heart or lung function problems can cause weakness which can make mobility an issue even if legs are fine. And arthritis in hands can make daily tasks difficult even if they can run up and down the stairs like champs. Or they could go deaf or blind or both. None of that gets into Alzheimer's, which is not guaranteed but is far more prevalent the older they get. People in their nineties are often going to have some sort of mental or judgment impairment. See: http://www.alzfdn.org/AboutAlzheimers/statistics.html
So you should also talk to your parents about their medical issues. Get a full list of their doctors and the medications they are taking
. In the US, so long as they are considered to be competent, their doctors can't divulge care information to you. I suspect things may be similar where you are. But talk to them about drug interactions because often there are a bunch of doctors and they are not necessarily perfectly communicating with each other. Five medications are almost guaranteed to have some sort of interaction issue. See: http://www.consumerreports.org/drugs/taking-multiple-meds-can-trigger-drug-interactions/
Plus there can be some nondrug alternatives. Your parents might benefit from some forms of exercise even if they aren't gym rats. Even daily or almost daily walking can be helpful for some issues, such as higher blood pressure. Even if they have mobility issues, getting outside is good for other things.
And by that I mean depression. It can be an issue for people, particularly if they are dealing with chronic pain.
Anyway, this is a lot to throw at you, and getting started early is not a bad idea at all. But your parents deserve to be a part of determining what their future is going to look like.