My advice. When PVP starts up put out worthless defensive units because every time he hits you you'll get points and can earn some good units. I sacrificed  nothing but Psilos, a few heavy defensive units and I keep the Psilos coming until the PVP is over and I earned over 240 Promachos. Great deal eh? When PVP isn't going just spend and keep your resources low so when he attacks he won't get much. Let him attack you. If he sieges your city let him.then attack other coalitions because when they retaliate it will be his units that get killed instead of yours. During PVP I always start fights to get cities to attack me and they usually do lol It's much easier than earning that many promachos through attacking or defending persian positions.

a coalition defence wall would be a lovely surprise for him if your coalition will support you on this :)