Family members keep coming back to a Hebrew phrase when describing Matityahu “Mati” DeNola: “manhig samui,” which means “natural leader” or, more precisely, “hidden leader.”

That’s fitting. Although only 23, DeNola was a young man of prodigious gifts and unseen torments, a former Israeli soldier of deep passions and even deeper struggles.

When he died Dec. 29 from suicide, the sorrow among those who loved him could not have been more profound. Yet his youngest sister, Sheli, helped calm down the grieving family when she told them, “We have to respect Mati’s decision.”

DeNola’s family members know he did not make that decision lightly. A Palo Alto resident, DeNola was a talented, thoughtful, caring man who put himself 100 percent into everything he did, including comprehending the bipolar disease that ultimately took his life.

“None of us can understand the kind of torture Mati went through,” said his father, David DeNola, from the family’s Palo Alto home. “We have tried to descend to hell with Mati just to hold on to him, but whatever he went through was infinitely worse.”

Life didn’t start out that way for the one-time star athlete, writer and artist. The son of American-born olim, DeNola was born in 1983 in Nahariya, Israel, and spent his first years on a kibbutz, though the family later moved back to the United States. From a young age, said his parents, DeNola showed great promise.

“What wasn’t he interested in?” asked his mother, Laura DeNola. “He was a star athlete in baseball and soccer. He went to the baseball playoffs in Czechoslovakia when he was 12 and pitched [with the Israeli national Little League championship team] to win the only game against the Russian team. He was a natural-born star.”

“He had a big heart and soul,” added his father, “and a charisma about him. Everyone who came into contact with him loved him.”

When he was in his early teens, DeNola accepted an invitation to join the Ha’poel Haifa soccer team, but around this time, signs of bipolar disease, for years known as manic depression, began to arise. “He walked away from sports,” remembered David DeNola. “This was a pattern. He would throw himself out there for others but he couldn’t be there for himself.”

Although the family was secular, DeNola embraced spirituality even as a teen. “One thing I noticed was his innate touch with the Bible and the land of the Bible,” recalled his mother. “We went back to Israel to get roots. If anything, Mati got it. He lived the Bible. He didn’t just read it; he felt it.”

At 18, DeNola joined the Israeli army, but his illness became more pronounced during boot camp. “He was very well thought of,” said his father. “He was made the heavy machine gun carrier in his platoon, but he started going into a severe manic state. He would stay awake days and nights at a stretch. We were not aware of any of this.”

DeNola was medically discharged from the Israel Defense Forces, and returned to his family in California. “The meds had terrible side effects,” noted David DeNola. “The devastation of washing out of the army is something he never got over. But Mati became an expert on the disease.”

Added his sister Maya, “He said if he could understand what was going on, he could control or fix it.”

Try as he might, the battle proved too great. “He had a demon on his back,” said Laura DeNola. “It just overtook him. We were ready to move to the ends of the world to get an answer.”

Added Maya DeNola, “I’m so proud of my brother, because he fought like nobody would for life. He did absolutely everything that he could.”

Matityahu “Mati” DeNola is survived by his parents David and Laura Belkin DeNola of Palo Alto; sisters Maya DeNola of Oakland and Sheli DeNola of Palo Alto; and grandmother June DeNola of Atherton.