I cannot read your order from where I'm sitting; but yes, if he doesn't identify his weeks by May 15 I would suggest promptly informing him of your chosen dates, ideally with his verifiably acknowledging receipt. Although policies can vary by court and depending on the terms of the order, ordinarily the court will allow you to pick when your time comes rather than keeping the custodial parent's summer plans in limbo because the other parent didn't meet a clear deadline.

