This is upsetting. Well… I can partially relate to this but the not learning part:
I also joined late this year (freshmen year) and we also have a useless teammate, he just sits around and does nothing but he fits because my team doesn’t take anything seriously and its all jokes but that does not have to do with anything.
You should involve yourself where you see best fit.
New Team Starting Resources is a great start.
But expect to hear others stories because I’m not really experienced.