Financial questions that need an answer

I have a parent who will be retiring soon, due to inability to work. They will be 62. I am buying health insurance for them, and this will be about 700 dollars a month plus medicine.

My question is, can my parent write this off their taxes?

Also, if not…what if my parent established a sole propriership or LLC? Could they then write off health insurance costs? Is the write off only equal to the cost of business expenses. Or will a good portion be reimbursed?

Thanks