Worried

Ok so my bf was dignosed in 2012 with brain cancer he went through kemo and radiation. Hes been in remission for almost 2 years. Now we're trying to concieve but here we are 7 months later and no positive tests 😔😔 doctors say we shouldn't be having an issue but im worried he may have bexome sterile due to treatment. Anyone here have a blessing from a male cancer survivor?