God knows, the next jump in prices are if you want a 1 bed or 2 bed, then you're looking at around 120k and then 200k, same leaselength issues and same cost of charges
Next up there was an option of a proper maisonette, the 30s style ones, on at 250k but its an auction property and the lease is 61 years, so thats why its cheap.
Anything that would meet their needs or her needs when he dies, is around 400k, 2 bed, needs a ground floor.
So financially not sure it makes a lot of sense to downsize given if she needs to, she could convert the whole downstairs into living and sleeping space.
This is outer London, she needs to be near her friends and things.