Hot take: I dgaf that Langdon turns the lights off for neurodivergent patients. Yes it's (initially) a sweet gesture, but it's not exactly ground breaking character development. The only reason he's being put on a pedestal for it is because he's a white man who "had his eyes opened" to the difficulties others face.
Accommodation isn't a one size fits all, one trick pony type thing. Mel turned the lights off for the initial autistic patient, because he was overstimulated and disregulated. He needed lower sensory input. Mel recognised this, and translated that into care she could provide. Langdon didn't see the logic behind it, and just assumes that's How You Accommodate autistic people. He literally steals the exact phrase she used.
If he really cared about accommodating Neurodivergent patients, he would have done research or taken a course on helping them.
Don't get me wrong, it is character development for him to be accommodating others needs in that way. But it's not groundbreaking, and if he was a female character it would be treated as bare minimum.