When those sexual urgings start, it is hard to get their attention, so I'm not surprised he rather play with Noel. Can you get Khai neutered sooner?
There are two low cost spay/neuter clinics in Newmarket (north of Toronto) and Barrie (a little farther north). I realize Brantford is a bit of a drive, I think it would be just over 2 hrs. in off peak times.