In that case, recite the Lotus Sutra-Guanyin Bodhisattva for your father. If possible, you can ask your father to recite the holy name of Guanyin Bodhisattva or the great compassion mantra in the future. The merits of reciting the Great Compassion Mantra will be rewarded, and it is incredible that the Great Compassion Mantra water can cure diseases.
I believe that the compassion of the Bodhisattva will surely bless your father. If his life is not over, he should recover as soon as possible, his illness will be alleviated and his pain will be less.
Don't think I'm superstitious and talking nonsense. Many people are sick, but how many people feel like you? There are many incredible things in Buddhism that the world has seen.