"As soon as something doesn't go the way he wants it to, he stops caring about it."
- "As soon as something doesn't go the way he wants it to, he stops caring about it."
"as soon as ~" 「〜とすぐに」
"something" 「ことが」
"doesn't go the way he wants it to" 「思うように進まない」
"he stops caring about it." 「それに気をつけるを止める」・「投げ槍な態度を取る」
He quickly becomes dismissive when things don't go his way.
『彼はことが思うように進まないとすぐ投げ槍な態度を取る』を英語で表現すると、『He quickly becomes dismissive when things don't go his way.』となります。
quickly: すぐに
becomes dismissive: 投げやりな態度を取る
things don't go his way: ことが思うように進まない
If things don't go the way he wants them to, he develops a really careless attitude right away.
この場合、次のような言い方ができますよ。
ーIf things don't go the way he wants them to, he develops a really careless attitude right away.
「彼は物事が思うようにいかないとすぐ投げやりな態度になる」
to develop a really careless attitude で「投げやりな態度になる」と言えます。
ご参考まで！
オーストラリア 
アメリカ合衆国 
カナダ 
