I found a letter from my dad's healthcare where they say they approved his x-rays, it also said 3 diagnostics. 1- solitary pulmonary nodule 2- wheezing 3- unspecified asthma he is 50 years old, and never smoked. should i be worried that its cancer?

Interesting, have you talked to your dad? It is his private information. The letter sounds like it basically approved an xray (or maybe CT? since unusual to need a letter to approve an xray). The three diagnoses would be the reason to do the test. The solitary nodule is likely the real reason and that needs to be followed and assessed by imaging to assess for cancer. Many nodules are no problem.

Cancer is one of the diagnosis that we fear the most and will have to be ruled in or out for the pulmonary nodule. Further imaging is likely to help with diagnosis that so far appears tentative and is rather descriptive. Keep in touch with current team specifically after above tests to get a good sense of the results and plans going forward.

It is impossible to tell on a plain chest x-ray whether a solitary pulmonary nodules is of any concern. There are a lot of possibilities that can cause a solitary pulmonary nodules, and cancer is not the most common of them. Especially in someone who did not smoke, it would be less likely, but it needs to be ruled out ASAP. He should not delay Getting evacuated. Good luck.