Since the son has no interest in guns, sell it. But we need a good photo of gun, both sides, and box to do a decent job of valuation for you. Could approach $1000 if perfect, but probably less.
I would never take a gun like that to a gun shop and expect to get anything other than screwed. Let me tell you a short story about that sort of situation:
More than 25 years ago I used to visit a small gun shop near my home once in a while, just to see what they might have. As I got out of my car, I saw an elderly lady leaving the shop and walking towards her Cadillac. As I entered the shop, the two partners--real jerks by the way-- were whooping and hollering, laughing and grinning. I asked what was going on and was told to open a large leather-bound case that was sitting on the counter. Inside was the most spectacular side-by-side double-barrel shotgun I had ever seen, engraved and gold-inlaid, fabulous wood, an extra set of barrels and accessories. I was allowed to pick it up and look more closely--it looked new, certainly mint. A Parker. I didn't know much about Parkers then, but relying on memory if it wasn't an A-1 Special it could only have been one grade down from that.
The gun had belonged to the lady's husband, recently deceased, and she had been told nothing about it by her husband. To her it was just his old gun, the one he had kept after selling his others before passing away.
Even 25 years ago a high-grade Parker like that was worth many thousands of dollars. They gave her $200 for it.
I often think about what might have happened if I had arrived at the shop a few minutes earlier. I could have told the lady she was getting cheated, 'tho don't think I would have been real welcome at the shop afterwards.