Hey OP so sorry to hear about your condition. I can empathise with you. I suffer(ed) from Keraroconus and did C3R treatement to prevent further degradation of my for cornea. But I can't get back my lost vision. My eyes are in bit bad condition and lenses specific to my condition don't work. I'm poor and can't afford other treatment. Like you I have to wear thick glasses. I understand what you go through OP. My parents are supportive enough though they can't afford. If my parents did what your parents did I would be happy to cut them off. You are not being entitled. Families helps each other out in need. If they could not afford to, it could be understood.

Many commenters suggested LASIK or PRK but if the OP has Keratoconnus or other corneal conditions they can't do the above mentioned treatment.

This may sound new-agey but I've been doing Yoga and Prayanama for last 8 months and there is a very slight improvement when I went for last Checkup. Now there is NO GUARENTEE that it'll work but there is no harm in trying it out. Who knows you can get some improvement.

Also they are some Ayurvedic treatment but they can't be relied upon but I've seen some people to have improvement, I had some slight improvement there too but it regressed back when I stopped taking Ayurvedic medicines. I don't where you live but do checkout. BUT be very careful there are lot of Fake clinics who want to scam you and they don't provide any treatment. Where I live it's very cheap and In theory it should be cheap. Also I don't know whether they have been approved outside of India so please very careful in this regard.

But you can do Yoga it's ok for most parts if you don't have blood pressure. Asthma or Joint troubles ... First consult your physician. Most of the physicians I've seen don't believe in Yoga and usually they don't have any problems with it.

I hope somehow you can get the money for your treatment. Hugs to you OP and feel free to Pm me if you need someone to talk to.