Welcome to HCM.
Since your friend has consulted many doctors and they are of the opinion that he does not have any problem, then it is very much likely that the problem he is having is purely psychological. But before coming to that conclusion a thorough investigation and examination is necessary. All the routine blood, urine and stool tests have to be done along with ultrasound
scan and if every thing is within normal limits, then you can be assured that he does not have any serious problem. In such case he may need psychological or psychiatric counseling.
Wishing your friend all the best.