Sorry to hear of your denial. It can be quite a shock.

Were you applying for a long term policy such as cash value or 20 year level term? A shorter term policy, say, 5 or 10 year level term may be worth applying for.

Do you have dependents you need to provide for/protect in case of your passing?

You also may need to wait a while longer since your injury before applying again. There are a few critical issues insurance companies look at. Are you receiving ongoing treatment for your TBI? Are you on long term medications for your TBI. Can you still drive?

If you get to a point where you are stable and maintaining your health, you may be able to reapply.

Did the life insurance company give you any specific reasons for the denial?