I'm going to force my brother to do something other than play soccer
Why do you want him to do something else?
I try to make him do something else for his own good
Maybe soccer is the only sport that he enjoys. You should not try to make him do other things. It comes across as controlling.
I have to encourage him to try more things, tennis is a good sport and it will help him in life.
I can see that you only want the best for your brother, and that is good, but you should respect his wishes.  If you want him to have more varied experiences, just ask him to play tennis (or engage in another hobby) together with you.  Make it sound like something that you want, and he will surely join in.