How to buy a house

I'm hoping someone can help me to understand if I'll be able to buy the house in living in.

Sorry. I'm low functioning and don't understand technical things to do with money or business.

We've lived in this house for most of my life, ever since I can remember and I feel completely safe and happy here. It's in the country, on its own and it is surrounded by fields and nature. There's no noise.

The house is from the 18th century, it's not in great condition, it does need work and lately I've been getting out and trying to do different things. It's not easy as I struggle with mobility but I like to try.

I can't work because of my health. But I really really want to buy this house, not just for my parents because they are older now and in poor health but also because it means I'll be safe in the future. We privately rent and we are friendly with the landlady. She is very old and I've been really worried in case she passes away anytime soon. I don't want to live anywhere else or worse end up in a mental hospital - that has happened to me before and it affects me even now like an ongoing nightmare.

Is there anything I can do to try and buy this house? I'm on benefits but I don't know if that will mean I can't buy the house.

I want to ask the bank or the landlady but I have no idea what to say and I worry in case they say no.

Is it possible for me to buy the house on benefits? 

I want to be here forever and I want my parents to be happy and safe in their final years.

Please if someone could help explain it to me I would be really grateful.