From the reading I've done, experts recommend that people recovering from or dealing with tbi stay away from a lot of caffeine. Although one cup of something caffeinated is considered to be ok.

I drink a cup of tea in the morning. Whenever I've tried to drink a cup after 12p or so, or had more than one cup, it really messed with my sleep in a bad way. I tend to get much worse cognitively when I'm tired so I've learned the hard way to not have more than one cup a day and to not drink it past noon.