At that time, he was having a hard time deciding what career he would want for himself.
He was having a hard time finding out what to do for his career then.
「迷い」ですが、「決められずにいる」と表現すると良いと思います！
At that time, he was having a hard time deciding what career he would want for himself.
その当時、彼は自分の進路を決めるのに苦労していました。
at that time：当時
decide：決める
be having a hard time -ing：〜するのに苦労する、〜できないでいる
He was having a hard time finding out what to do for his career then.
その時、彼は将来何をするべきか見つけられず迷っていた。
find out：見つける
what to do：何をするべきか、何をしたいか
日本 
