Our GP diagnosed a hernia in my OH years ago. On referral to a consultant...............no sign of a hernia, discharged, and then, almost 2 years later a complete blockage resulting in removal of his sigmoid colon due to a volvulus. Do mention this possiblity when you speak to the doctor/s. A hernia, in my knowledge, is a rupture in the intestinal wall where the intestines poke through, whereas a blockage is a very serious problem which can be corrected by a colonoscopy, as it was the first time it happened with my husband, but a recurrence resulted in much more serious intervention.I honestly believe that the suspected hernia was a compaction of the bowel which did correct itself before we saw the consultant, but as the bowel had been stretched it later led to a volvulus and then a sigmoidectomy. This solved the problem but we are very aware that it can happen again.
You don't say how old your grandad is, nor do you say what his other health problems are, BUT after 17 years of Parkinsons we are still fighting and carrying on as best we can, so 10 years may just be a hiccup in progression or not.However, if your grandad is is his late eighties it may be a different matter so, you need to speak to the medical staff concerned with his care.
The swelling in his arms and legs sounds like a heart problem to me, fluid retention, but I am no expert, only know that this was the case with a parent.SO, you really need to speak to a medical person regarding your concerns, ASAP, nor rely on any input, as well intentioned as it may be on a forum.None of us are experts we can only relate our past experiences.