Blood Is Thicker Than Water
(members of the same family share stronger ties with each other than they do with others)
Hi, Gina. I'm here to pick up your truck. Remember? You promised to let me borrow it for the day.
That I did, but I'm going to have to disappoint you. My brother took the truck this morning to pick up some furniture at a warehouse. He needed it right away, so I gave it to him.
Boy, that really leaves me high and dry, but I guess blood is thicker than water.
Don't take it personally. This was a very pressing matter. Besides, he should be back in a couple of hours. Then the truck's yours. By the way, I gave my brother the truck because he needed it right away, not because family members share stronger ties with each other than they do with others. I would have done the same for you if you had been in his position.
should be back - should = ～のはず