Is a counsellor or psychiatrist best
I really think that the Dr. who prescribed something already did as he saw fit and if a specialist was needed a referal would have been given. If the doctor he already saw was his regular MD and has been his md for any length of time then he should just stay put, his GP has an advantage of already knowing the patient, the patients history, any applicable family history. Plus your relative already has a trust built up with his regular md that is very important when it comes to discussing certain matters of the heart, body, mind and ones mortality. Sometimes important details are not revealed to someone who is new to a patient especially if the patient does not think it to be life threatning.
I hope that I have not bored you too much with details, and I hope I have helped somehow. I also wish you and your family the best. Tell your sibling not to make a mountain out of a mole hill. And to give the tablets a try and to let someone 73, so old enough to make his own decsions, make them. Good Luck
a psychiatrist
A counselor is simply someone to talk to and make suggestions. A psychiatrist is actually a doctor. They can prescribe medication if needed and have much more training in dealing with actual mental illness. If you suspect an actual mental condition then they need a doctor. If they are just stressed then a counselor might work. Good luck.