Don't Worry about Reminding the bereaved parents of their child. They want to hear their name, they want to know that others remember besides them.
Don't say "God must have needed your child more than you"
"God must have bigger plans for your child"
"He/She is in a better place"
"There is a reason for everything"
It is silly to think anyone needs a child more than his/her own family. Unless you are some higher power and know the "reason" stay away from that.
Do say "I'm so sorry for your loss"
"I'm so sorry for your loss, I can't imaging what you are going through"
"I'm so sorry for your loss, I lost (fill in the blank) and know how painful it is"
"I'm thinking of you and your family, I'm so sorry"
