Your information correlates with what has been reported in the discussion on
ancestors of Owe Thörnqvist, that one of his ancestors did emigrate to the Caribbean islands. Owe Thörnqvist appearantly did some research of his own, and ended up visiting a Turnquist family living in Jamaica.
Thus I find it likely that Owe would enjoy hearing from you, but as for contacting him, I'm not sure how to go about it. According to a newspaper article a few years ago, he has a permanent residence on the west coast of Florida, USA, but he will perform in Sweden this July (at Dalhalla for instance).
You could try contacting his agent, EMA Telstar at info@ema.se, to see if they can forward a message for you (I doubt they will provide you with his postal address, but if you point out that you are a relative they may be more willing to assist you).
Vi dansar rumba i Engelska parken,
vi har planterat en kaktus på marken,
en liten palm från en blomsteraffär,
den ställer vi här
i Engelska parken...