Seipel had been battling kidney cancer. His friend posted the news to Seipel's Instagram account.
During the final week of the regular season, Seipel left hospice to see the Browns clinch their first playoff berth since 2002 with a victory over the visiting Pittsburgh Steelers. Seipel watched the game in a suite at FirstEnergy Stadium provided by Mayfield's wife, Emily.
"You're extremely inspirational," Mayfield said in a video sent to Seipel at the time.
The Mayfields also met Seipel after the game.
On Saturday, Mayfield tweeted: "Rest In Peace Tom. Your pure heart will never be forgotten."