Can someone help me with some medical history.?

Hi i have a question regarding my husband, it all started about 4 months ago. He's been losing weight in the last 2.5 years he's lost about 40kg. But in the last 2 moths he's been having very lose bowel movement. He can go up to 10 times a night with a couple of days between. He's also suffering because everything we go to have sex he's unable to get it up and it is frustrating him. He's not bleeding when he goes to the toilet. Umm its not gastro we've ruled that out. But if someone can give me some advice on what could be wrong with him. Im not asking for a diagnosis or anything. Just some advice on what it may be. Thanks