NotSpaghetti
Why is everyone assuming the very worst?
Let's not assume we can see into someone else's heart and soul here!
Give him a chance.
He may have asked her and she may have said "ask me again in six months"....
Not unheard of by the way.
You're right - we don't know what's going on between the couple, it's possible he's still holding on to it in good faith and that, for whatever reason, he hasn't yet proposed.
But - I cannot imagine any man that I know not understanding that a ring, handed down to DD's mother by her mother, is a precious keepsake. He could have asked the OP to hang on to it for that very reason until he was ready to ask DD to marry him.
That he didn't doesn't in itself make the man 'dodgy', but it does show a degree of thoughtlessness.