I understand the emotional side of this predicament, but really this is not what council housing is all about, or it shouldn't be! Council housing is about providing affordable housing for people whilst they are in need. The tenancy was granted to your friends mother when she was bringing up her family. Once your friends mother has passed away, the house will I am sure be reclaimed by the Council as information from searching the web would indeed state that you need to be a tenant for a minimum of 12 months before you have any rights to buy. There is no other wasy to do this. Sadly there is very little chance of either of the people involved getting any sort of mortgage or loan to purchase the property at this late stage of the game as most mortgage application forms will ask for medical history, and have the right to ask for medical reports. This does not just apply to the insurance side of things.
It is sad that your friend will have to say goodbye to the home he has shared with his family, but I fear this is exactly what he will need to do. That was maybe another family will be lucky enough to enjoy the home as he clearly has with his mum over the years.
If you take away the emotional attachment you all have here, you will see that everyone is speaking sense in your answers, and not just giving their opinion. Sometimes you have to accept what you don't want to hear.
We wish you ALL well in the difficult times ahead.