Confused and need help.

My son was diagnosed with beta thalassemia trait in 2014. Dr said he would of inherited this from his dad. (Dad is turkish). Me (mum english) and my child's dad divorced and he remarried and they're expecting a baby. My child's dad got tested for the beta thalassemia trait and was told he doesn't have it, so i got myself tested and i don't have it either, so we got my son tested again and again my son's test show that he has the beta thalassemia trait. How can this this be possible? If both mum and dad don't have it.

It isn't possible, meaning that one of the test results isn't accurate. What type of testing was it? DNA testing should be able to pinpoint the exact gene mutation or deletion.