This response, in one of its extremes, is wonderfully brazen: looking everywhere except the body for the body's corporality. And, from that, we can learn, to look at sidewalks and buses and buildings as places where corporalities reside too. If we take out the bit about it being done by humans, we can see that corporalities reside in jungles and rivers in ways not necessarily created by a society, and they exist in the cracks in the sidewalk caused by rain, too.
But the body itself ends up being hidden. An approach that separates the natural (impairment) from the cultural (disability) stops us being able to talk about the natural. And the important thing is precisely the frontiers we draw between the two, and how some things give the impression of being physical and inevitable - someone's body, for example, or a medical condition.
What Mateus did in his personal life and daily encounters was to influence other people's reactions to his physical condition: through explaining, or through legal action. There are many different coordinations that can be made: the person that saw Mateus in a motorized wheelchair could've said, hey, that's quite expensive, he's probably not asking me for money. As Mateus gets to know people, his employers and colleagues included, they understand him in different ways.
Our own theorising has to keep up with what people are doing in practice. The separations and connections between the body and the social are very real questions in people's lives as they manage and negotiate their corporalities.
A reference for the "social model of disability" is Oliver, The Politics of Disablement (1990). In my critique of this model, I'm using the critiques Butler makes of the division between sex and gender in Bodies That Matter (1993).