Make sure you're not pushing them very soon at all. Concussions are a very serious thing. They deal with the head and all your functions go on in your head, in your brain, and it's just very important to give them, make sure they're taking enough time to ease into things. Some people will go back to their normal life too fast and it's not healthy and they're just a mess because they haven't given themselves enough time to recover.
I think the way that someone could support someone suffering from a concussion is not by pushing them or pressuring them to recover. It's hard to tell when someone is experiencing symptoms of a concussion because not often are they the symptoms presented externally, they're internal symptoms. And so just letting people recover at their own pace, not pushing them to perform or return to normal life is really important in how you could compassionately support those undergoing those experiences.
Just be kind to people who have concussions because it's hard and sometimes you feel just kind of useless if you can't do anything. So just being kind, it's that simple.