My dog struck by car on head. What can I expect during recovery after surgery?

My almost 3 year old boxer got struck by a car on his head and incurred some head trauma injuries including some broken teeth and a punctured nasal cavity and an oblique bone fracture on his jaw (sort of like a cracked egg) and some hemorrhaging his right eye. The nasal cavity puncture was making the top of his head in the middle of his eyes sort of bubble up when he would breath. So he was treated for shock and then had surgery to repair puncture and 2 teeth were pulled out. Doctor said he was doing well and recovering the few days he was in the animal hospital. When he was released he was already up and walking, eating and relieving himself. Only thing him and I were still worried about was the hemorrhaging in his right eye. He said the dog could not see perfectly on that eye due to that but that hopefully the swelling would go down. The doctor put him on pain meds, antibiotics and some vitamins. He has been home 3 days so far and seems to be improving day by day. But my question is that he does not seem to be himself, he seems a bit off sometimes and dozes off into oblivion a lot turning his head left to right. I hope this is just due to all the head trauma and surgical procedures, I do not want him to suffer for the rest of his life. He has had 2 mini "seizures" i believe and the doctor said to give him a little Childrens Benadryl which I did but that seemed to make him breath heavy for a few hours last night. I have not given him Benadryl since. He does seem to be getting better but he is just not himself yet. I know he just needs time to recover but do any of you know or had had your pet incur the same behaviors after similar injuries and procedures?