Tim Tebow just shared some heartbreaking family news ... revealing his father, Bob, has passed away at 78 years old after a battle with Parkinson's.

The former Heisman Trophy recipient delivered a touching tribute to his dad on Friday ... saying, "Heaven ushered in a hero of the faith last night as my Dad was welcomed home!"

While Tebow acknowledged his friends, family and fans will say "sorry for your loss," he has a different perspective ... as Bob was a "hero of the faith" who is now "home."

"I asked him last week what he looked forward to most about Heaven, and he simply said, 'Jesus,'" Tebow wrote.

"He couldn’t wait to see Jesus face to face. Praise God that his wait is over. Death has been swallowed up in victory. He’s healed and whole now."

"So we don’t mourn as those with no hope. See you soon Dad!"

The tribute included photos from some unforgettable moments for the Tebow family ... including when Tim and his wife, Demi-Leigh, announced they were expecting.

Rest in peace, Bob.