He “had a hard war,” according to the barkeep at the pub in Little Hangleton. He was wounded and walks with a limp. He takes up as gardener for the Riddles and avoids people for the most part, disliking noisy, crowded places since he came back from the war (GF1).
Bryce came home quite a few years before the end of the war in 1945, undoubtedly because he was wounded. He was working as the Riddles' gardener by they were murdered in the summer of 1943.