I am asking for help with my father’s treatment (prayers, advice, financial assistance).

Armag, believe me, I went through all of this when my late sister was ill. We also tried to treat her with all sorts of methods, visited different healers, as many as we could find, but it was all just a waste of money. And I was convinced by my own experience how many charlatans make a fortune off people's misery. So, my advice to you is to find a good oncologist and a clinic, and all these pseudo-scientific and other means are just a waste of time and money.
Stay strong and don't lose hope and keep a clear head; maybe the diagnosis won't be confirmed after all.