About 20% of deaths for those aged over 65 take place in a care home. The average duration of care home residency is 13 months but most are a lot less.
Meanwhile only 4% of estates pay inheritance tax. That's a ridiculously low percentage.
The number of estates that are reduced from a significant inheritance to a pittance due to all the money being spent on care is very low, but it does happen. No one knows who it will happen to, so the right thing to do is to spread the risk evenly among those who are at risk, so that everyone loses a bit, rather than a few losing everything.
My proposal is that every individual who reaches the age of 65 with their name on the deeds of any real-estate property, or in possession of other capital assets worth more than £50k, should be required to assign a 30% time-delayed share of those assets to HMRC, retaining a lifetime interest to themselves (ie they don't have to sell their home or hand anything over, but that fraction of the asset is eventually no longer theirs, though they can still enjoy any return on the investment etc during their lifetime). With that in place, all elderly people who end up needing significant care could have it freely, because everyone with assets is sharing the cost.
When the person eventually dies, if the assets are sold then the Government gets its share then, or the inheritors could have an option to enter a shared-ownership agreement and paying rent on the portion that the Government now owns.