I know it's called 'Choice based letting' and there will be a generic housing list that people must join in order to bid for either council or RSL homes.
The chances of anyone getting social housing are very slim due to the housing shortage. In fact the only way you go to top of the list is when your homeless, in hospital and they want to discharge you because you're a bed blocker and cost £££s a day.
If you're already a secure tenant in a specially adapted home they won't kick you out unless you voluntarily want to leave. If two people share say a two bed accessible flat and they have a joint tenancy, if one dies then the remaining tenant still has the right to remain in the property.
If you disagree then quote the part in your tenancy agreement that says different.