esophagus cancer

My father had a stent put in his lower esophagus after he found out he had cancer so he could swallow. He didn't have surgery, just chemo and radiation. He's been finished with his treatment for about 2-3 months and the tumor shrank which let his stent fall into his stomach. I believe it is a metal stent. Does he need to have this stent removed? Will it pass by itself? His current Dr says to leave it in his stomach. Just wanting your opinions because he's concerned about leaving it in there. If it needs to be removed, how will they remove it?