S.M.
Yes you must treat everything,the yard (often) his pen, blankets, the kids rooms and the rest of the house-in and out. You might want to call a service like terminix-they treat all "bugs" and then if something keeps coming back they generally don't charge much if any at all. We fought fleas one summer and they kept coming back and treated the whole house in and out and the garage too. (Even though the dog never was in the gargage) the point is one little flea can hide and stay alive when you think it is done. Get a flea comb for the dog and use it too. it works on cats if you need to do them too.