So I Have A Molar That Is Breaking Apart On

So I have a molar that is breaking apart on the top right side of my mouth. I had it examined and was told it needs a root canal and that its dissolving the tooth next to it. The hole in that tooth tries to hold food every time I eat. So I have to create suction and get the food out or rinse and swish to remove it. Now on top of that I've had pain in my lower right side jaw and if I squeeze the gums in the area top or bottom, I get a foul smelling white plaque come out of the gums. What should I do?