Wa `Alaykum As-Salamu Wa-ramatullah Wa-barakatuh

 

You can start by paying Fidya for each day missed (feeding one person per day missed) and keep the intention to make up days if your health becomes better. I wish you wellness, but from what I understood from your description that such illness might be prolonged for quite bit of a time and that’s why I feel paying Fidya is first and sufficient insha Allah.

 

Keeping in mind your health issues you mentioned, I assume you might be able to make up these days too, so calculate in average how many years you missed and if you have the money to feed people (30 persons per each year) then you should do it. If you do not have that money, you need not to do anything at all.

 

You only need to make up that day, masturbation breaks fast and the Kaffara is just making up the day.

 

Almighty Allah knows best.