I dont know what to say really but, I didnt want to read and run....
I think you done well so far.
FIrst thing is to give him a bit of support and reassurance. Put a smile on ( even if you dont feel that way) and tell him the tests arent always right and in most cases the sperm count is something can be improved... You need him to be positive and hopefull and willing to work on this little project with you.
Second is you, have a bit of a cry because it is sad to hear it, even if this is only a test and even it is a wrong test. Take a bath and/or eat some ice cream.. they will both help in almost all cases. 😉
Third, say the same things you said to him..Tests arent accurate and you can work on numbers. This is only the start of the journey. Unless he has zero sperm this is still something to work with.... and once you start the process, it doesnt matter how much far you need to do and what method you will use. They can go in and take the sperms if it is what is needed... and even if there is no sperm, there is donations .... just try to stay positive.
Fourth is the action. Call your GP and tell them you want to talk to them about this test. Both of you need to start that process with your GPs. I know we should't bother the GPs and NHS with time wasting stuff but GPs are still working, and I think it is is still important and I dont think it is time wasting. I dont know your age but trust me, if you want kids, dont put it off (older sister advice from me).
Fifth, relax.... you have just dealth with the first (in)fertility drama.... Nothing is straight forward, nothing happens fast and there are many twist in all our stories. The most important thing is to stay positive and dont let bad news to paralise you. Always find an action in every event and challange... for example, Research supplements to support the sperm numbers, check out the web sites of some fertility clinics - they detail different options... even join in an open evening... they have them online now.... you can listen and even ask question.... As long as you find an action and follow it through....
And always .... we are all here if you need a chat. Good luck .... trust me, it will work out well 😊