By Christopher Rosen
October 06, 2015 at 02:57 PM EDT

Teenage YouTube star known as Caleb Logan Bratayley died from a previously “undetected medical condition,” his family announced via Instagram on Monday night.

Bratayley, who appeared on his family’s popular YouTube channel “Bratayley,” died on Thursday at 13 years old.

“This has come as a shock to all of us. Words cannot describe how much we will miss him,” his mother, Katie, wrote on Instagram on Friday. “His incredibly funny, loving and wonderful spirit made us all fall in love with him as a YouTuber, friend, brother and son. We know you tune in to watch each day and eagerly anticipate new videos, but ask that you bear with us while we deal with this tragedy as a family. Please help us honor our, baked potato.”

On Monday night, the Bratayley family posted again on Instagram, citing the unnamed medical condition as the cause of Caleb’s death and announcing a memorial service would be held in his honor.

“Caleb’s death has raised many questions about how and why this could happen to a seemingly healthy boy. Sadly, tests have confirmed today that Caleb passed away from an undetected medical condition,” the family wrote. “We’ll have more definitive answers in the coming weeks but ask that you help us celebrate his life instead of focus on his death. Due to an outpouring of support and people’s hope to be part of his memorial, we have decided to live-stream the ceremony [Tuesday] at 8 p.m. EDT.”