Yes, it's a weird place for a door-frame but you can see the horizontal steel beams in the inter-floor space (I don't know what that's called in English) and the ceiling beams are obviously not floating on top of the brick, they are supported by vertical beams somewhere. The concrete brick is just a covering, none of those walls are structural. Though there's a way of building with structural brick and steel beam, but this is not it. The thing with steel beam is that it's deceptively stiff. You might think that it's too thin to be structurally sound, but structural steel beams can carry a lot of weight and resist deformation rather well. This is obviously not a professional construction, it's just not up to rich developed world standards, but like I said, that doesn't mean the building will fall.