Hi, I Am Asking For A Friend. He's Been Experiencing

Hi, I am asking for a friend. He's been experiencing Hives (He's had them for at least a week and I've bought benadryl but the hives havent gone away), loss of appetite (sometimes), dizziness, having trouble sleeping, nausea/vomiting, diarrhea( at least 5x a week), and blood in poop. Just wondering what could be causing all these symptoms. I've given him benadryl thinking it was an allergic reaction, but it hasn't helped the hives, and Motrin hasn't helped also. He seems to think it could be liver cancer, but I am not too sure. Any help would help out alot. thanks in advance.