I See The Light by Arden O’Keefe

Heath had always been a misfit—a weirdo who went all over town in a tank top and shorts even on a coldest day, who claimed his dog could talk to him, and who saw this blinding light every Christmas Eve coming from the woods behind his house that no one else ever saw.
Even his mother made all sorts of excuses to stay far away from him. If it had not been for his grandma—who loved him despite all his oddness—he would never have had anyone to call his own.
The night before Christmas, with the silliest plan in mind and his coward dog tagging along, he set out to find the true source of the mysterious light he could see from his window. When he found the cheerful bunch of elves gathered around the magical bonfire, celebrating like kids high on sugar, Heath could not be more excited. Then, finding out that he was half elf and half human gave a meaning to his life, finally understanding the reason behind his weirdness.
Buddying up with a cute elf named Shea for the night, to see what it meant to possess the magic of an elf, Heath was to go on a journey to spread the gift of happiness amongst those who had been good this year. But when the night came to an end, he was asked to make a decision. Whether he should embrace the magic of the elf within him completely, or become a plain, old human, and go back to living an ordinary—though slightly odd—life, back in the world where he had never been accepted, and to the universe which didn’t have Shea in it…