This condition is called sleep apnea where the brain is not getting enough oxygen function and the patient feels rousey also he wakes up shivering in the night and feels shortness of breath. I would advise you to get a consultation from and respiratory specialist. Your father may have to take bipap oxygen treatment for a few days. Wanna get his blood pressure tested and if the wait is very high there should be targeted reducing the weight. Hi wait causes all these kinds of problems.