翻译：他每次路过母校都不忘顺便探望他的老师。(every time)

这里倒装句最好了
Every time passing by his school，he never forgets to visit his teachers （by the way）.

He never forgets to look in on his teachers every time he passes by his old school.

He never forgot to visit his ex-teachers everytime he passed his Alma Mater

He passes the alma mater every time and he does not forget to visit his teachers.