Dear Friend,
From the information that you have provided I infer two reason for your father's problem, one is due to cardiac cause ( very common in diabetics), other can be due to acid reflux from stomach. I suggest you see a cardiologist, if there is nothing wrong with his heart, then get an upper GI endoscopy done.
Best wishes.
Answered2015-10-19 10:09:03
Let others know if this answer was helpful