A friend of mine had two diffrrent cancers. would his children be more prone to get cancer?

Genetic Predispositi: Not all cancers have genetic predisposition. It depende on what type of cencer(s) your friend had.

Gene or chemo: Occasionally, a person can have a change in his dna which predispose this person to develop cancer. In addition, if one has cancer and undergoes chemotherapy, certain chemotherapy itself can cause damage to normal tissue and cause therapy related secondary cancer.