An Army soldier who lost his arms and legs during his third tour in Afghanistan last week underwent surgery Monday as supporters from around the globe offer prayers and messages of hope on a family website.

Army Staff Sgt. Travis Mills, of Vassar, Mich., was injured when he stepped on an IED April 10 while serving with the 82nd Airborne in Afghanistan as part of Operation Enduring Freedom. He is recuperating at a hospital in Germany and hopes to return stateside on Tuesday, three days after his 25th birthday, his father told FoxNews.com.

"He's in a tremendous amount of pain right now, but he's sleeping," Dennis Mills said. "But as far as I'm understanding, his vitals are good. But it's still early."

Mills said he last spoke to his son on Sunday.

"He was pretty upbeat," Dennis Mills continued. "He has his moments, but he was doing really well. He sure is looking forward to getting back to the good ol' United States."

A website dedicated to Mills' status, www.travismills.org, contains updates on his road to recovery and provides links on how to donate money to offset expenses related to his medical care, including some expenses that will not be covered by insurance, according to the website.

"Travis was scheduled for surgery [Sunday]; however, they said he is stable enough to wait until Monday morning just so everything is freshly done before his flight home," Mills' wife Kelsey wrote. "The nurse told me what an honor it is to be with Travis, and what a great man he is, and how everyone there loves him (as well as everywhere else). She was able to finally give him a glass of milk and he was so happy."

Mills is only the fourth quadruple amputee in military history to survive his injuries, according to the Tunnel to Towers Foundation and the Gary Sinise Foundation, which have reached out to Mills' family to offer support.

Mills was "overwhelmed with joy" when a chaplain and a Wounded Warrior representative presented him with a Purple Heart and his wedding ring on Sunday.

"He thought it was gone forever," Kelsey Mills wrote.

Dennis Mills said relatives received a call informing them that Mills stepped on an improvised explosive device (IED) on Tuesday. Travis Mills was later taken to Kandahar and elsewhere in Afghanistan for treatment before being flown to Germany.

Mills' wife -- who lives in Frisco, Texas, with their 4-month-old daughter, Chloe -- said he underwent a third surgery on Friday to clean his wounds and that doctors did not see any signs of infection, the Tuscola County Advertiser reports.

A day earlier, Mills' wife posted on her husband's Facebook page that she was "astonished" her husband survived.

"I have never been a truly religious person, however, in this time, all I can do is turn to prayer," Kelsey Mills wrote. "I am astonished that my husband has survived against all odds, and he is still in a fight for his life."

Mills lost both of his legs above the knee, his right arm above the elbow and his left arm below the elbow, according to the post.

"While sustaining the worst of the injuries, he was still trying to help his soldiers, because that is the kind of man he is," Kelsey Mills wrote. "He is the best man I know, and he does not deserve this pain. If I could take it all away, I would. The only thing we can do is be there for him in his darkest hour and help him find his way home.

“Keep the prayers flowing: It’s the only thing any of us can do while feeling so helpless. He has sacrificed more than anyone can imagine for this country. He is a true American hero, and he deserves all the respect and love in the world.”

Three other soldiers were injured in the blast, but Mills, who took the "brunt of the explosion," was mainly concerned with their condition, David Pratt, Mills' close friend of 12 years, told FoxNews.com.

"He was the one who stepped directly on it," Pratt said. "But the only thing Travis was concerned about was his guys. That's the kind of soldier he is."

Click here to visit Sgt. Travis Mills' Facebook page.