“I’m not happy about opening a business in Jordan,” said Noman Sarhan, who was an aviation maintenance worker at the Damascus airport before the war. “I don’t want to put down roots here, but I have to consider all the possibilities.”

He settled in at home, inside a large building where his family rents an apartment and space for the salon next door. Family life eases his nerves. When his 4-year-old son got a nosebleed, he joked, “Bashar shot me,” referring to Syria’s president, Bashar al-Assad. His 7-year-old daughter, who just started attending a $70-a-month private school, was the only one absent.

In Dara’a, Feda Sarhan owned a popular hair salon that was looted and burned to the ground five months ago. Some of her old customers have started trickling in here, and word of mouth has drawn new ones. She is content with building a Syrian clientele. Jordanians have held protests against Syrian refugees in Mafraq, and she fears being caught in any trouble.

“We don’t mix with the Jordanians,” she said.

As the eldest son in the family, Mr. Sarhan grew up knowing that it was his duty to look after his siblings.

But taking care of his younger brother Hasan and other relatives, as he was doing now, was threatening to sink him. The war’s shifting nature gave little hope of a way out, for him or for his country.

Since early in the war, he has supported the Free Syrian Army, the Western-aligned rebel group, but he was now worried about the rise of Islamic militants. Early on, he believed that Sunni Muslims like himself and Alawites, members of Mr. Assad’s minority Shiite sect, were galvanized by a shared quest for democracy. Now he fears that the war has lasted too long, that too much blood has been shed, that too many will seek to redeem their losses.

“I know that there will be revenge killings in Syria for the next 10 to 20 years,” Mr. Sarhan said. “Some of the rebel groups will take revenge against men, women, their children, the young and old. They will not leave one Alawite alive.”