So I ask you can science explain this?
Is your contention that cancers never go into spontaneous remission? That when you get cancer, it is inevitably a one-way journey? "You've got cancer - you will definitely die"?
Fact is, many people are diagnosed with cancer.....and many people get better. Some of them go on the operating table and say "Allah I'm in your hands now" or "Ganesh I'm in your hands now" or cross their fingers, or just hope - and sometimes the same thing happens to those people as happened to your dad.
Equally, some people get on the table, say "Jesus I'm in your hands now" and die on the table, or die soon after.
Sometimes people get better. Sometimes they don't. There is no significant imbalance in the percentages of Christians getting better over Muslims, or atheists over Hindus - nothing to show that one worldview "works" and the others do not.
It's a nice story - and I am glad your dad got better - but it means nothing.
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To close, let me leave you with this. My sister was a comitted Christian, as was her husband and both sets of parents. Regular churchgoers. She went into hospital to have twins - but there were complications. She, her husband, the parents, the entire congregation, all prayed for her to live.
24 hours later she was dead. She never even held her children. They will grow up never knowing their mother. She, too, effectively said "Jesus I'm in your hands now".
Sometimes people get better, and sometimes they don't. That's all.