grub killer every year in late May/early June that takes care of their "babies" in the fall that eat your roots. Know that this is a long haul fix. If you want to kill them instantly (though with yours the damage is mostly already done for the last year) you have to use a different grub killer.

This is the instant grub killer - https://www.lowes.com/pd/BAYER-ADVANCED-24-Hour-Grub-Killer-Plus-10-lb-Insect-Killer/3353712

Then the maintenance/every year killer is the scotts stuff -

https://www.homedepot.com/p/Scotts-Grub-Ex-15-lb-Season-Long-Grub-Killer-99605F3/202745002

For you, I would put down new seed and a top dressing right away if you can afford to keep it wet until it germinated and grows a bit. If not, it won't really start recovering until this fall.