Worried About Diarrhia, Leg Pain, Fatigue, Chills

I have a friend that I am really worried about. About a week ago he felt really bad. Ran a fever and had bad chills. After that his throat got a bit sore and his tonsils got swollen. Since then, his tonsils and throat have gotten better but other symptoms have occured, for instance, diarrhea , fatigue, a strange rash just on his hands and feet that will come and go in a matter if minutes and sores in his mouth. Also last night he got a few blisters on his ears. I am really worried about him and i am looking for some help. Everytime he goes to the hospital in the past the doctors here never find anything. He has a history of kidney stones and had his gall bladder taken out about a year ago. He also has a cyst on one of his kidneys, but every doctor that we mention it to doesnt seem to be worried with it.