Complicated questions are his favourite sort, normally - though he'd hoped for a different answer than this one. The best here isn't worth anything we have at home...except that it is, in this case.

There's nothing in the world, this one or any other, that he could offer equal to her brother's life. By comparison, his love is a mere consolation prize. He's not so melancholy as to assume that it's worthless - but he'd like to think he can be at least somewhat objective about this. She's from a time when she can't trust that he'll offer more than mere friendship, and her brother has been at her side since before their birth. They won't balance out for her.

"...A while, then." All he can offer is a sympathetic frown, one filled with a feeling he's acquired honestly. It's the sympathy of a man who'd be similarly torn if any of his siblings staggered out of the woods. "We might as well enjoy what we can."