Could Redness At The Back Of Head Of An Elderly Person Be A Matter Of Concern?

My 84 year old dad just fell backward down 7 steps and hit head on bathroom door post. No broken skin is now sitting in chair and complained of gas pains (burping a lot) and asked for alka seltzer. Says not in pain right now but area on back of head is red. He now wants to lay down which is where he headed to do initially.. Should I keep him awake?