Thank you for your question
My name is Clare
I shall do my best to help you but I need some further information first
Has any legal action been started?
Has the Parent actually threatened legal action i writing - or just verbally?
There is no action that your parent can take.
It was clearly a gift - it was after all offered as an Engagement Ring for your wife - to whom you are still marrried
In addition there has been no change in the legal status between you and your parent so even if it had been conditional on your remaining a family member - legally you are.
I cannot say who they have consulted - nor of course what they have told them - but there is no court action which can successfully be taken against you
Please ask if you need further details
No there is no such legal process in the UK - whatever age you are