I'm so sorry that it took so long for you to get a reply. I'm very happy to assist you. :)
Yellow feces are indicative of bile. Liver, pancreas or gall bladder issues are several reasons for this, so I truly have to urge you to see your vet with your boy for some blood work. He's probably due for his senior bloodwork if he hasn't had any in the last year or two.
If the stool is soft or diarrhea is present, this could effect the anal glands, which may be infected or impacted. He will need an antibiotic if there is infection. If they are impacted, the vet can clean them out for him. If they are inflamed, they are going to be sore so I don't recommend that you try to clear them yourself.
Below is a few links for you to check out, both on the color of his feces and regarding anal glands (please copy and paste them into your browser:
I know you probably wanted a home remedy for this, and I truly wish I could give you one. I can suggest feeding
him a bland diet of boiled chicken
and rice (no skin, trimmed, no seasonings) until you see the vet with him, in case it is pancreatic or gall bladder related.
It has been my pleasure to assist you and again, I apologize it took so long for assistance. Please remember to rate my personal service using the 5 stars that are shown. If you have any further questions regarding this topic, please feel free to reply and I'll get back to you as soon as possible.