ITS NOT A DAMN EASTER EGG
Indeed, he's in Half Life 2, when you get to Kleiner's Lab, you see him on the screen next to the room with the H.E.V. Suit in it while scrolling through the stations, you can no-clip around outside of the map and find the small area he's in, there's also a Metro Cop there who is also not so detailed in some parts
Type in thirdperson to see an untextured, unanimated model from HL1!
Doesn't it have a breathing animation?