I had a good friend back in middle school. He was kind and nice, and already ready to help others.
When i was in secondary school, i had a friend who was so nice and willing to help others.
When I was in secondary school, I had a good friend, who was always kind and ready to help.
at the time when i was in secondary school/middle school, i once had a friend who was kind and alwas wanted to help the others.
或
i once had friend in my secondary/middle school times, he was really warm-hearted and always there to help the others.
我想LS的朋友是想说 he was kind and nice and always ready to help others