Marriott Stellaris in Aruba is beautiful, romantic, and safe. The island's not terribly big but there is some cool stuff to explore around it. People are friendly and the main town is fun to explore. the regular rooms are very large--I was on points too and chose not to upgrade because the rooms are large and the bathrooms enormous. It was a wonderful vacation; I highly recommend it.
We stayed at the Renaissance La Concha in San Juan. If your grandson and wife-to-be want nightlife - this is the place to go. Also, surrounds lots of restaurants, beaches, has nice pools...etc. About a $15 cab ride to old san juan - which has some great restaurants and sight seeing. The hotel also has relationships with some excursion companies so they can go rapelling, kayaking etc.