An autistic teen found underneath an umbrella of dense brush after four days in the wilderness was doing well at a hospital Friday, asking for food and smiling at relatives who came to visit him, his family said.

Jacob Allen, 18, was discovered Thursday sleeping under a thicket of laurel in the Dolly Sods Wilderness Area, part of the Monongahela National Forest. He had survived four cold days and four nearly freezing nights.

His mother, Karen Allen, spent the night in the hospital, keeping watch over her son.

"He was alert, asking for food and wanted to get out of bed and walk around," she told NBC's "Today" on Friday.

It was the wilderness — a cascade of mountain laurel and rhododendron flowing over loose rock and steep cliffs — that posed the greatest danger to Allen while he was lost. But in the end, it was the one thing that kept him safe.

Though Allen was less than a mile from the spot where searchers had found his hat Monday, the brush kept his location hidden until Thursday afternoon. State Police 1st Sgt. Jim Wise said he believes it also may have kept the teen from wandering toward 20- to 30-foot cliffs.

"It made sort of like an umbrella, but underneath it was bare and open," Wise said. "It made some type of shelter."

Allen opened his eyes, then rolled over to meet his rescuers when Jeremy Reneau called his name.

"He was very quiet," said Reneau, 25, the first to spot Allen. "But you could tell by his body language he was hungry."

After a quick meal of candy bars and peanut butter sandwiches, Allen tried to walk with rescuers but tired quickly. Reneau, Wise and others carried him on a litter to a trailhead where 50 people, including his parents, awaited.

"There were tears. There was clapping. I was crying. Other people were crying," said Tiffany Curran, a volunteer firefighter.

Allen was in good condition at Davis Memorial Hospital in Elkins, where officials said he remained under observation. His parents, 14-year-old brother, Micah, and 22-year-old sister, Brittany, were with him.

"We are just relieved and just so happy, happier than in the past couple days, that's for sure," Micah Allen said Friday morning.

He said that even though his brother is nonverbal, "he's obviously 10 times happier. You can tell he's happy to be with us, he's smiling when we walk into the room."

Micah Allen said he expected his brother to be released from the hospital Friday.

Jacob Allen wandered away from his parents Sunday afternoon on the Boar's Nest Trail in Randolph County. Hundreds of volunteers and trained professionals had been combing the woods, calling for him to come to them for candy bars, ice cream and other food. After each shout, they listened closely for rustling brush.

Overnight temperatures dropped to as low as 38 degrees the first night Jacob Allen was in the woods, wearing only a wind jacket and wind pants over his T-shirt and hiking boots. However, rescuers said hypothermia was not a concern as long as he stayed dry. Some scattered showers hit the region over the four-day period, but the search area remained dry and temperatures slowly began to rise.

"Every day, it just got warmer and warmer and warmer," Karen Allen told "Today." "It was like God breathed some warm breath on us here in the mountains."