Mystery snail very sick. posted ? 3 days ago, no answers. please help me help him!?

Hes been getting a white mucusy discharge. At first it was only out his breathing tube. But now its comming out both sides. As 4 ppl it wud b both ends. Yesturday he was on bottom of tank all day upside down, so i took him out cuz i didnt know how long they can go w o comming up 4 air. I put him n a fish bowl in 2 inches of water. At 1:30 a.m. I got up 2 check on him. He was up on the side of the gl at the top of the water, but this morning at 8 a.m. He was back on the bottom, closed up with this white goo oozing f both his breathing tube area n his digestive/Mating area. What is it? What do i do about it or 4 him? Will he get better or is he dying? Ive had him 6mo. His gf died 2mo ago. Didnt have this white stuff. Im raising their babies that r doing great. Born in late aug. Early sept. Some that have shells an inch across. I raised them n a separate tank as the adults b4 putting the biggest 1 n tank w him. None of the babies r sick. Reply here or email me at heywood.melanie@yahoo.com please help!