Father can't wake up no matter what we try.

 but he looks like he's just sleeping. My father tends to have bad dreams and sometimes will that wailing in his sleep and start having cold sweats. we are used to it and its also easy to shake him and wake him up. tonight weall shouted and moved him around even inflicted a bit of pain using a sternum rub but he thinks whatever we are doing, is part of his dream in the sense he will reply to us but he's definitely asleep. how do we wake him up? he is 67 years old and doesnt have a very good diet because he doesnt eat much. what is going on should i call an ambulance?