Phil is first seen at the Veterans Day celebration, where he and Garrett exchange banter. Their conversation is painful for Kelly to watch, though, due to the absence of a third friend.
Like Garrett, Phil is a combat veteran, but Phil joined a year earlier. He separated from the service after hearing the news of Garrett's injury and Mickey's death.
Phil appears to have some degree of belief in the folklore of Grunwald, because he advises his wife not to drive along Farm Road 138 through The Green Ravine River Valley after dark. Sammie does not listen, however, and her car is pushed off the road.
Phil breaks down when he learns Emma Lee is lost in the woods, leading Kelly to send him to the hospital after Sammie rather than join in the search effort.
When the town is after Kelly for the alleged kidnapping of Laylah Flaherty, the forest boy, and the assault on Garrett, Phil assists in the search for Kelly out of Sammie's concern for her mental health. Phil drives his truck into the woods. It is implied to be a large pickup truck or utility vehicle, as it is capable of driving through the riverbed and following Kelly to the clearing.
During the battle with the Grim Halberdier, Phil tries to assist the police by keeping his truck's mounted searchlight beam focused on the villain.
He presumably keeps Emma Lee in hiding while Sammie goes to assist Kelly in confronting Eld Stagger.