TTC worried couple

Rosalinda
I'm so worried, but don't want to lose my positive vibes...my husband and I are TTC and it's been two years now. I have a 4 year old son from a previous relationship so my husband wants a child of his own, but my husband had a major surgery done three years ago on his intestines and says that he can no longer produce sperm. I've spoken to the surgeon and she said that that area was never touched so he should be fine. My obgyn is sending us for some lab work and she said I should be fine since I already have a child so she wants to get a sperm count but how would she get one if he can't produce? I'm scared that this is the end of TTC and that I will never be able to have more kids. He is so sure that nothing comes out he doesn't want to do the lab work. Is this it? Or can my doctor get that working again?