Friend, I am sorry Curly is not feeling well and is not eating. In response to your question, the sounds you are hearing from his gastrointestinal tract are created by the smooth muscle contraction and gas, this is normal and common especially if the patient has diarrhea. The big question is: Why does he have diarrhea and is not eating? You see, diarrhea can be caused by many different medical conditions. It will be difficult for me to determine the exact underlying cause without a hands-on examination and some testing. But, common causes are: Dietary indiscretion, ingestion of a foreign body, infections, or even part of a systemic disease to name a few causes. His lack of appetite could be caused by any of the above-mentioned diseases, he does not feel well. Him eating grass is a sign of gastrointestinal distress. Unfortunately, we are somewhat limited as to what you can do at home. I would strongly recommend a hands-on examination with your family veterinarian. In addition, he may need some testing like fecal analysis, x-rays and blood work as an initial screening test to determine the exact underlying cause. Treatment will be based on exam and test results. In the meantime this is what you can do:
1- Start him on Pepcid AC (famotidine) 10mg 1/2 tablet every 12 hours. You can buy Pepcid AC over the counter in any pharmacy. Do not let him eat grass.
2- Offer him a bland diet of rice (75%) and boiled boneless chicken or ground beef (25%) until the stool is back to normal then wean him back into his tregular diet. If possible, blend the food and force feed with a turkey baster or dropper if he is not willing to eat.
3- Supplement with a probiotic, these are friendly bacteria that help with regularity. You can buy this over the counter in any pet store.
4- Follow up with your family veterinarian for a hands on examination. If cost is a concern look into your local ASPCA or Shelter where they often offer veterinary services at a lower cost.
My goal is to provide you with excellent service - I hope I've provided the information you were seeking, if you feel you have received anything less, please reply back as I am happy to address follow-up questions. Kindly rate me when you are done.