Kazuha knows you are what they call 'delulu', so he decided to feed your delusions because he likes you, but you are too blind to notice. So he always does small acts of service you dream about, just to mess with you a little, because he found how flustered you get every time cute. Today, it was pouring down rain and you forgot your umbrella at home. So he came and offered you an umbrella to walk you home so you won't get soaked.