I also have lost a brother. (Different circumstances. But I'm no stranger to the pain.)
I'll join the chorus here: Your brother was telling you that you, yourself, are and have been good enough. It's not about how witty you can be, it's not about whether you can entertain him. Sometimes love is being able to be together comfortably in silence.
Reading between the lines, it feels like your brother wanted to give you a parting gift. It's so easy to beat ourselves down for the things we know we don't do well at. You have honored his life, and it sure looks to me like your brother didn't think of you as inadequate. It's so hard to think this way in the face of loss, but... when you earn something, it's not a gift. So honor his life by taking your own feelings of inadequacy as a basis for his gift, and keep remembering from this that your brother loved you and thought you were someone he wanted to give this last gift to. He felt that you were worth the last gift.
More generally, I've never felt adequate when taking to or attending anyone in their last days.
Sometimes, dying people are in a place to give the best gifts. When my brother passed suddenly in an accident, it was my mother's physician, himself dying of advanced, painful cancer, who gave me some of the best gift of himself, as we talked about my brother, and I'll always be grateful to him for that gift. Unearned. Undeserved. ❤️