Suggest Treatment For Memory Loss Post Third Degree Concussion

My husband experienced a 3 red degree concussion 7 yes ago. He has mild executive function deficits and memory loss. He doesn t seem to be making new memories since. Recently, he cannot state all of our oldest grandchildren s names 13 and 8 yrs. old. (Born before the concussion). He is 60 yrs old. Is this a sign he may be developing dementia?