Hi Kandy and welcome. As Darlene posted above there is a forum specifically for TBI/PCS, lots more information is available there.
Some additional specifics about your fiancé’s concussion history would be useful. Anger and other forms of disinhibition are not uncommon with TBI survivors. When was his last concussion, and did his behavioral symptoms get worse after that? Has He been seen by a neurologist or clinical neuropsychologist? Often they help identify specific problem areas and prescribe appropriate treatments. Therapy and sometimes medication can help with these types of behavioral issues, but it assumes he is aware on them and is willing to work to try to resolve them.
Meantime some general information about TBI/PCS can be found on the links below.
Best to you both.
http://www.brainline.org/index.html
http://biausa.fyrian.com/state-affil...bia-of-indiana