You ask a good question - one that many have wrestled with in an attempt to get a clear and concise answer.
Thankfully, only God reserves the right to judge someone's heart, as no man is capable of seeing things that only God can see. God does not give us eyes or discernment to know what goes on inside a person.
The Bible says that God is all loving and all merciful, so we can be sure He looks at His created ones with such passion and indescribable love. No one will ever know what went on in the mind and heart of this young boy, but God does, and will judge him accordingly.
I do not have the spiritual authority to confirm the eternal destination of anyone, but Jesus does -
In addition, the Father judges no one. Instead, he has given the Son absolute authority to judge. John 5:22