65y/o male, w/colostomy bag, surgery 13wk ago&nothing but sick, vomiting some blood, dehydrated, feces in stomach, bags don't work. Lost faith in doc. Advise?

Bowel obstruction. You may have a bowel obstruction or abscess from resolving infection. You need IV fluid, possible ct scan or xray, bloodwork and possible antibiotics. Many early bowel obstructions within weeks of surgery resolve with conservative medical care. Call your surgeon or go to the hospital if you are feeling really sick.
Go to ER. If dehydrated and elderly, with vomiting, and sick--this is too complicated a patient to try to 'nurse' back to health at home--go to er for evaluation, blood tests, imaging, and IV fluids / medications. They may be able to identify what is going on. Call ems/911 if cannot get him there on own.