The My 600-Lb. Life star died on Feb. 17 of complications from an infection, his father, Matt Milliken, announced on Facebook, according to TMZ. He was 29.
"Sunday he was having problems with his breathing, they were able to resuscitate him and a short time later his heart stopped," Matt said, according to the outlet.
Sean first appeared on My 600-Lb. Life in 2016, when he was bedridden and weighed around 900 lbs. He and his mother, Renee, moved to Houston so he could get weight loss surgery, through which he successfully dropped 400 lbs.
TLC said in a statement that they were "saddened" to learn of Sean's death.