Siding against the Brotherhood before Blind Betrayal turns him hostile, removing him as a companion. Siding against the Brotherhood after Blind Betrayal results in Danse no longer interacting with the Sole Survivor. ... The issue effectively removes Danse as a companion but it will not remove his perk.

What happens if you take Danse to the Prydwen?

Under these conditions, asking Paladin Danse to accompany you will prompt a warning that while he is travelling with you both of you will be considered enemies of the Brotherhood. Any Brotherhood of Steel members that you come across will be kill-on-sight.

What happens if you let Danse live?

If you were able to keep Danse alive, then he will head to the top floor with you. As you are leaving the listening post, you are greeted by a very upset Elder Maxson, who has some harsh words for the two of you if Danse is still by your side.