Horrible news for 'Teen Mom' star Amber Portwood: Her father passed away unexpectedly at the age of 50 earlier this week.

Shawn Portwood Sr. died on Tuesday (Dec. 16) after undergoing liver surgery in Florida. "He was put in an induced coma on Friday after liver surgery at Orlando Regional Medical Center," his son Shawn Jr. tells the Daily Mail. "We are making burial arrangements now."

Amber's father was vital to helping her get her life back on track during the past year. The 24-year-old reality star had well-publicized struggles with addition and spent 17 months in prison following a December 2011 arrest on drug-possession charges.

"I know that he helped Amber because he gave her strength to get better," Shawn Jr. says. "He is the reason she was able to turn her life around. He set the precedent for what she needed to do to get better."

"My dad was the most important person in Amber's and my life," Shawn Jr. says. "He was a very strong-willed person and even though he was battling illness for a very long time, he never gave up. He didn't give up on life. He didn't give up on his family. He didn't want to give up."

Our condolences to Amber, Shawn Jr. and the rest of the Portwood family.

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