Has anyone witnessed their loved one have an attack of involuntary whole-body stretching?

This sounds like a seizure, you need to tell his doctor.

I agree with cwillie, it sounds like a seizure. There are different levels of seizures that can occur and you will want to report this right away to a doctor because these things are best caught early. If you can do a video on your phone or some such for the doctor when it's happening that can be a helpful tool for the doctor as well.

Although we are always happy to listen and there are often forum members who can share valuable insight, I would say that yes you are in the wrong forum. Your loved one is in pain, daily, and something is causing it. You need to discuss this urgently with his doctor.

That's not stretching.
That sounds like the muscles are locking up - I have a friend and that used to happen to her legs all the time.
Talk to his doctor. I don't know if Physical Therapy might help, but ask about it.

Emma Sue:

I think it's great that you are asking for input on the forum, sort of like crowdsourcing for medical diagnoses.

A lot of people have been helped with rare disorders through such groups.

I am sure you have already mentioned this to the doctor.

It can be frustrating when you mention a symptom but the medical staff can not seem to find a cause.

Also, there are a lot of people with medical backgrounds who post on forums.

I have actually read several times about people who got answers on line, when the doctors they were seeing seemed stumped.

There is lots of wisdom to mine in massive crowds.

I hope you find your answer.

Your dad is lucky to have someone like you who has the intellect and intellectual curiosity to be proactive and seek their own answers rather than being slavishly and naively obedient to doctors only.

My mother was once experiencing fatigue and leg weakness that caused frequent falls.

It came on suddenly, but her doctors did numerous tests and said there was nothing found.

It turned out she was recently put on Metformin. Metformin is known to deplete b12 and worse many elderly lack the intrinsic factor that converts b12 to the active easily absorbed form.

I put her on Methylcobalamin (active b12) and a within days her symptoms resolved.

All her doctors had missed this very simple solution. 

Definitely he should see his doctor asap (IMHO), anything that causes pain should trigger a trip to the doctor, the very least we can do is keep our aging LO out of as much pain as possible. There are several things that could be causing this, Parkinson's isn't the only or even the main possibility in case your worried about that but of course it's always possible. This sounds more severe but simple deficiencies, which are common in the elderly, can cause this type of thing making it easy to fix or it could be a symptom or indication of something a bit more complex, either way only a medical professional is going to be able to diagnose it and help bot of you. Good luck and I for one would be interested to hear what they come up with so please come back and update us if you remember.

Definitely call his doctor. It sounds like the symptom doctors call "dystonia" or "dystonic reaction". It may be caused by some type of medical problem (such as a seizure or another neurological disorder). Or it could be caused by a severe medication reaction. Sometimes dystonic reactions also causes a person's eyes to roll up and get "stuck".

After reading all the answers, I think I'd escalate it to an ER level event and go today. If the duration is becoming longer, I would think that's a warning sign. Go now and find out what's going on.

Thank you all for your wonderful suggestions. Have an appointment set up. I suspect it is neurological in origin just need to distinguish whether or not Parkinson’s or worsening remnants of past cervical fusions. Thank you all very much

Has anyone looked into "stiffman" syndrome?