My son says he would like to become a walking encyclopedia when he's older.
My son's big dream is to be the kind of person who knows about everything.
ーMy son says he would like to become a walking encyclopedia when he's older.
「息子は大きくなったら物知り博士になりたいそうだ」
to become a walking encyclopedia で「物知り博士になる」
ーMy son's big dream is to be the kind of person who knows about everything.
「息子の大きな夢はなんでも知っている人になることです」＝「物知り博士になること」
person who knows about everything で「なんでも知っている人・物知りな人」
ご参考まで！
カナダ 
