boxers do shed
My late and great boxer, Beau, always shed alot, year round, but his hair was so short it probably would not have been noticeable had it not been that his coat was white, and I often tried to wear black. It wasn't noticeable in the house, but very evident on the dark apholstery of the car( where he travelled often) My new baby boy, Lenny, is brindle and I don't see his hairs anywhere yet. Your pup looks definitely mixed, body shape looks wrong, but he is cute, he sort of looks more mastiff.