Daniel Coleman is sharing a heartbreaking family update.

The creator of the popular YouTube series Danny Go! announced that his 14-year-old son Isaac Coleman died after a battle with stage 3 mouth cancer.

“Oh my sweet boy,” Daniel wrote on Instagram May 22. “There’s so much I want to say, but I don’t know how yet. I already miss you so much, and the pain in my heart is far more than I can process.”

“But looking through thousands of pictures and videos this past week,” Daniel continued, “I’m also filled with tremendous pride. Your 14 years were full of so many challenges, but you met them all with such grit…and you somehow kept your trademark joy in spite of it all.”

The 40-year-old—who shared Isaac, as well as son Levi, 11, with wife Mindy Coleman—went on to express all Isaac meant to those around him.