Doctor said to my dad he have colon cancer but the biopsy result was ok it show that is just polip. His blood test was ok aswell. What we should do now?

Repeat colonoscopy. Unless the pathology report comes back on the polyp as showing malignancy, he will need to have a follow-up colonoscopy to look for new polyps in the future (1-3 years). The timing will depend on risk factors, such as a history of ulcerative colitis, strong family history, completeness of colonoscopy, biopsy findings. If the pathology shows cancer, he should see a colorectal or general surgeon.
More information. I need more information to give you an answer. Was there cancer in the polyp? You don't say what kind of biopsy it was or what blood test was done. I would suggest you speak with his doctor to make sure you know what he had, what risk he is at for more cancer, and what treatment, if any, he needs.