Considerable Weight Loss, No Change In Appetite, No Change In Bowel Movemnts. Reason?
It is understandable that you are concerned.
Unintentional weight loss always has to be investigated. This is weight loss with no change in activity level or no decrease in oral intake.If his activity level has increased in the last few months due to increased hours at work then it is possible that this has contributed to the decrease in his weight.
The other causes are : (1) cancer- blood test however would normally show a decrease in the blood count/hemoglobin, increase in ESR ( this is a test that checks for inflammation in the body,it would be high in cancer),
There may be also abnormalities in the liver or kidney function. The fact that the blood tests were normal is reassuring. A chest xray and blood test for the prostate should also be done
(2)high thyroid hormone levels/hyperthyroidism- again your doctor would have likely tested for this
(3) Infection
(4) HIV
(5) depression, stress or anxiety
(6) persons with a history of chronic illnesses
The camera in this throat (endoscopy) is to look for any lesions in his stomach which would normally be associated with vomiting, loss of appetite and abdomianl pain.
The colonoscopy would look for any lesions in his colon.
Both of these would determine is there are any tumors in these areas that may cause the weight loss. These would the most common tumors. If these tests are normal then it is likely that he does not have cancer.
I hope this helps, feel free to ask any other questions