Weight Loss, Severe Fatigue, Hair Loss, High Calcium Level, Loss Of Balance, Coughing. ENT, Cardiac, Body Scan All Normal. Suggestion?

Question: I have a close friend who is seriously ill. Over the past four months, he has lost 30 pounds, has major fatigue, has been to his internest, cardiologist, and nothing is showing as abnormal in test results. His calcium level tested high, which led to a thought that he might be with hyperparathroidism. He was tested for this at Cleveland Clinic and results sent somewhere in California for review and he was told they were inconclusive. He has been traveling on business and after being away for a almost a month, I was frightened by the way he looked. Hair loss which I thought I noticed before. I know he returned via a long flight and drive, but it has never taken its toll to this extent. He seemed almost disoriented and I could see that when he was walking, it was like he was 'off' and stumbled once or twice. His eyes looked a bit sunken in. And he was coughing. I asked when that started and he said, last week ... his voice sounded hoarse as well. He drank some chamomile tea but would not eat anything. As background, he is in his late 50s, biracial caucasian/caribbean black. He has spent sigificant time in the caribbean over the past few years including rural areas with parasites common amonst the people. In addition, he was in Military, served in the Gulf War. If anyone can direct me to a good diagnostician, in Florida or NYC or anywhere, we will get him there. I ask for your thoughts please.
Note, I don't expect a diagnosis. What I seek is a logical set of detailed recommendations for how to basically go from A to B to C to D re diagnostic decision tree.And hope for a recomm in Fl or NY or anywhere that can provide this in one place. We have found Cleveland Clinic great for dealing w a specialist,have never needed to begin with an internist and move through the process there. Saw ent because he felt as if there was a lump in throat when he swallowed but they found nothing, his cardiologist checked him out and found nothing , had body scan, nothing showed up. Frightening because he is getting worse. not diabetic either

Thank you. Diabetes has been ruled out.

I am certain the thyroid profile has been done and hyperthyroidism has been ruled out but I will reconfirm this.

Chronic hepatitis B and C ... can a person be symptomless and then have it kick in? I have to believe this was checked but I can't know until I check.

I am certain HIV has been ruled out.

I dont think TB testing was done and since he does travel to a place where difficult TB strains are present, it is a good idea, however the coughing just started.

CT scan was done but need to check that abdomen was included.
Nothing found to date.

With calcium level elevated still and parathyroid testing inconclusive, can you advise re any follow ups to this.

Can you recommend diagnostic team in New York City ... our other option is Mayo Clinic.

Thank you so very much.