Hi Michelle. Welcome to the forum.

This is going to be a shock, of course, but as you already know testicular cancer is highly curable. There is every chance that your son will have the surgery, spend a bit of time recovering, and then get on with the rest of his life. 

When it comes to telling friends and family, everyone has different ideas. When I was diagnosed with prostate cancer, I immediately phoned my sister, my wife's brother, and a few good friends to let them know. I didn't keep it a secret at all, and it meant that there was no pussyfooting around the topic. 

I can sort of see that waiting until more in known is reasonable, but at some point the rest of family have to be told, or they will find out anyway and then may be upset that they weren't told sooner. Believe me that not telling someone because you don't want them to worry is a strategy that only works for a short time. 

Please keep us posted of your son's progress. We're always here if you need to talk. You can also speak to a cancer nurse on the phone using the number at the bottom of this page: 0808 800 4040. They're available during UK office hours, monday to friday..