Remus. You do not give the value of your house.But say it is worth £150,000. You could probably only take out £75,000 on equity release.
This would not be enough to buy a property in the south, just provide a deposit. You would then need to take out a mortgage to pay for the rest of the house.
If the flat you buy costs £250,000, you would have a £50,000 deposit. The rest would go in buying expenses including stamp duty. You would need a mortgage for £200,000 and to get a mortgage that large you would need an annual income of around £60,000 minimum.
Your best solution would be to sell your current home and tuck the money you get away somewhere safe and then rent a property near your sister. The money from your flat could be used to top up your income to pay the rent.
Google 'rented retirement homes sisterstown'. This will produce a list of possible retirement homes in her area, or if you are not bothered about having a retirement home, look on Rightmove.
from someone who estranged from daughters for more than 20 years