My 62 Year Old Husband Started Feeling Bad About 5

My 62 year old husband started feeling bad about 5 weeks ago. He has severe lower belly pain that radiates to the side and back. He is rapidly losing weight, he is now under 200 lbs and his normal weight is 215. He has been to the doctor and they did blood work for gallstones and Kidney stones. No blood. They did an ex ray and found nothing. They have sent him 2 times now to have a cat- scan. The only thing they have found is a small nodule on his Thyroid. They did an ultrasound and he now has to wait 2 weeks for them to test that. Meanwhile he feels so bad he is missing work and this man never misses work. Should he go to the emergence room?? Would a nodule cause this much pain