Could this be a sign of cancer???? Help pls?

So today my brother told me that something hurt and asked where and he sort of pointed at his penis and I freaked out and I took of his pants (I'm a guy) and asked him to point where and he pointed at his upper thigh around the waist line and I grabbed lotion and rubbed to check him I found a ball the size of a small pea not noticeable unless you feel around and I'm worried I told my mom and she checked him to and she said were going to get him checked out at the doctors I just want to know what to expect he six and plays alot and he is always hitting himself in his boy parts we try to avoid it as much as possible but its not like we can stop him from playing pls help ?!