A sweet caring guy who is most likely broken on the inside but always puts someone else's needs before his, doesn't care what other people think about him
Girl 1: hey did you see that guy
Girl 2: yeah he's like a brother to me, he's such a Tyler
"Tyler" is named stereotype (similar to "Karen", or "Chad", but with a different role in the pantheon of named stereotypical personas).
A "Tyler" is someone who is extremely contrary, and due to being overly sheltered, their entire value of self worth is derived by constantly correcting everyone around them about all the things they were brainwashed with in highschool.
They have trouble accepting new information that conflicts with their existing world view, and even when confronted with evidence, they will instead insist on parroting back their pre-existing programming as a 10 page essay in the Facebook or YouTube comments section.
Susan: yeah, fvck you, "the man"!
Tyler: Well, actually, "the man" isn't a specific person...