WOAH!!! TWO VIDEOS IN ONE DAY??? I'm proud of myself right now :) But since this is such a sad scene, I can't give myself a cookie right now T-T but anyways
This is "The Palm of a Tiny Hand" (Romaji: Chiisana Te no Hira, Japanese: 小さな手のひら) from Clannad Original Soundtrack, with lyrics (Romaji, Kanji+Furigana, English and Vietnamese).