If you do it every time, he'll vary on how he makes his first move, but as long as you always get the board down to a 1-2-3 or a 1-4-5 on your second move, you're guaranteed to win.

Yes, removing 4 from the bottom row creates a 2-3-4-5 set up from which he cannot recover from if you continue to play correctly.

In addition to taking four from the bottom row, taking four from the other two rows are also safe moves, because they also create "safe" positions. (0-3-5-6 and 1-3-4-6).

John