Only two winning "leaves" are 7 and 14
So since he can go first and can leave 14 he can't lose

Leaves :
1 to 5 obviously lose
6 draws
7 wins
8 to 12 all lose - next player wins with 7
13 draws - next player loses - last player wins

Take 1 and leave 14 wins - next must take 1 (2 to 5 lose) and leave 13 to last player for a draw - last player also loses with 2 through 5 so must also take 1 to leave 11 for a draw - first player takes 4 for the win by leaving 7 - next player must take 1 for a draw leaving 6 for last player who loses to the first player who left the 14

JW Three Rivers CA