How we cite our quotes:
"You must see the garden front and the fountain." He leaned forward and put the car into gear. "It's where my family live." And even then, rapt in the vision, I felt, momentarily, like a wind stirring the tapestry, an ominous chill at the words he used – not "That is my home," but "It's where my family live." (1.1.83)
Sebastian feels distant and separated from Brideshead because he so resents his family. He can never appreciate the estate the way Charles comes to.
"I'm not going to have you get mixed up with my family. They're so madly charming. All my life they've been taking things away from me. If they once got hold of you with their charm, they'd make you their friend, not mine, and I won't let them." (1.1.106)
Remember what Anthony later says about charm? Interestingly, Sebastian says his family manipulates with charm, whereas Anthony claims Sebastian does this very same thing.
"Perhaps I am rather curious about people's families – you see, it's not a thing I know about. There is only my father and myself. An aunt kept an eye on me for a time but my father drove her abroad. My mother was killed in the war." (1.1.128)
We expect Charles to be drawn to Lady Marchmain as a replacement for his own mother.