TTC & issues

We are TTC but my SO is 300lbs, 6ft tall, and 37 years old. I am 5'3 and 139 very healthy, and 23. Do you think this will affect his sperm and cause fertility issues? I'm so nervous we are going to have to do IVF or some type of fertility drugs to conceive! I'm worried with his weight issues and age! I also think he has erectile dysfunction sometimes which doesn't help and when he cum's it's never a lot!!  What are your thoughts??