Help for my 16-year-old son, or – maybe the Quran is right?!

Hello Rabbi
My son was recently exposed to a relative his own age, and following the conversation with him, he feels that something has shaken him. And it seems to be a relatively deep shake-up.
I will focus on the question, even though it has different layers, and I probably won't cover it all:
After all, Muslims and Christians are also safe on their path, so what should motivate me to act and believe in the path just because I was born into it?!
I'm very happy that my son asks such questions, but I'm telling the truth because inside myself, after all the years I've been dealing with this, I still don't have good answers, I'm just in some kind of process on the subject.
Does the rabbi have a way to provide an answer?