The answer to your question is yes but.
It is certainly possible for a moon of a giant planet to have a ring, but the key word in your question is “stable”. What do you mean by stable? A year, a century, a millennia, 50 millennia, a million years? Any of these might be considered “stable” at some level.
The problem is that asking how long such a ring would last for is a very complex question. It would depend on the orbit of the moon, the mass of the moon relative to the planet, the presence of other moons, their sizes and orbits and many other factors.
But as a thought experiment to suggest that it should be possible, consider a series of cases starting with a Jupiter sized planet and a moon, could the moon have a large ring – debatable… now imagine increasing the mass of the planet in stages eventually the planet is so massive it becomes a brown dwarf and then a star, by the time it’s a star the moon is better considered to be a planet.
Could a planet have a ring in a binary system, I suggest yes it could.
As the mass of the planet increase so does the stability of the moons ring, but how much mass is required to produce how much stability is very difficult to say.