As a lover of Parga my choice for you would be Kassiopi, pleasant walks up round the headland and the castle, plus just like Parga peaceful with no 18-30 type tourists, you could let your son have some space and still be confident that he is safe.
There is good choice of Taverna's with several nice bars on the main street and down in to the harbour. I can recommend Strofilia located at the square, Janis Restaurant and for a special meal Trilogia.
Take a boat in to Corfu town either during the day or the evening excursion is nice, I can recommend Cosmic tourist office in the main street close to the square for excursions.
If you want a day out book an excursion to Parga and Paxos
Graham