Jack did a great interview on 32 Thoughts. It's during the "Twelve Carat Rib Injury" episode; starts at 49:00.
He talks about his brothers (obviously), makes fun of Zegras for being a NY country club boy. He praises Nico a bunch saying he's underrated because he plays against top lines and it isn't about the numbers for him. Plays through a lot of injuries. He also gets into what part of his game he has been working on the most and he says his shot. References how Matthews has that deadly toe drag snapper so I'm hoping we see Jack blast a few of those this season.
In regards to Luke, he mentions that he is still battling the injury but should start skating next week (not sure when this was recorded). Also mentions that he is living by himself this year and is going to bring Luke in next season. Jack is a hype guy by nature but man, after hearing him talk about his brother's potential and having Nemec come in for them to be the 1/2 for a long time, you can't help but get an erection that last longer than 4 hours.
EDIT: Quinn also does an interview at 33:00. It's cool to hear his perspective on Jack/Luke as well.