You might find a cruise book from that period. If you know what division he was in you could check out the picture of that division and he might be in it. Check navysite.de they have a link to cruise books. There is a cruise book on there for West Pac 1968 - 1969. I hope this can help you some.
There is Kitty Hawk vets page on Face book you could try there maybe someone knew your father in law or could help you more.