Dominate Person has a Wisdom Save. Subtle Mass Suggestion, they need to hear the suggestion. Isn't your telepathy limited to one creature at a time? I think you'd need to say something for that to work.Not, his spells are totally imperceptible.
Subtle Dominate Person, or Subtle Mass suggestion and force them to fight against themself.
I'd recommend Dominate. Dunno which to recommend, though.