I don't play tau, but I saw the first few lines of your post and thought I'd let you know that if your friend is infiltrating and fleeting with Kantor, he's cheating you something hard. Now, if he's using Shrike, that'd be right.
I don't know the Tau codex so well, but some general tips against that are:
>Start with your valuable units deployed in terrain. If he wants to jump over and get you he'll have to make dangerous terrain checks and probably lose a marine or two.
>Lose combat. If you've got something that will let you reroll morale in your army, make sure that it doesn't affect the "outer most units" in your deployment. If you lost combat, yes, you lost a unit, but then you've got a magnificent turn of shooting against him.
>Go first. I know, it's random to a point, but if you get the chance to go first I'd suggest you take it. You can then mauever and shoot Shrike's unit.
>Reserves. If all else fails, you could just hold your whole army in reserves. Won't be terribly effective the rest of the game, but it'd be just like going first where you'd get shooting on Shrike before he assualts you.