Looking for a Doctor with experience dealing with Orthostatic Hypotension

OK, so this is not what is usually posted here, but I am a SAHM with 3 kids (8, 6 & 2) who has taken on the responsibility of caring for my ailing Father-in-Law in our home. He has several health issues, but the one that is most troubling and difficult to handle is Orthostatic Hypotension. Basically, when he is lying flat, his Blood Pressure goes dangerously high and when he stands up his Blood Pressure drops dangerously and he is at great risk for falling.

I am looking for a doctor with experience dealing with Orthostatic Hypotension in Parkinson's patients with Diabetes. Can anyone share the name and number of a doctor who may be able to help us manage this better?? We live in Frederick, but we are willing to travel for the right doctor. He is a veteran (Marine), so military doctors are an option as well.

Thanks! ~ Beth