The two sisters brought with them a chocolate cake from the nearby grocery store and put candles on it: two red hearts, and a neon orange 2 and 5. Their brother had turned 25 in April, but he could not properly celebrate his birthday in a Russian prison.

They brought along other things, too: a carton of Winston cigarettes, lighters, a bottle of Coca-Cola, some chocolates. The things that he liked, the things he had not had for so long. The sisters wondered: Would he still have his sense of humor? Would he still be the same?

And then they waited for their brother, Yurii Dobriev, like they had been doing for the past 18 months, alongside about 150 other people who were also waiting for their loved ones on Tuesday afternoon in a parking lot in the Chernihiv region of Ukraine, a couple hours north of Kyiv.

The buses were coming, they were told, carrying 205 Ukrainian prisoners of war. They had just been exchanged with 205 Russian prisoners, the 64th prisoner exchange of the war, one of the largest so far.

“We are very anxious — whether he’s really there or not,” said Anastasiia Dobrieva, 31, one of Mr. Dobriev’s sisters. “We just want to see him as soon as possible. It’s incredibly emotional for us — we haven’t seen him for a year and a half.”

Each person in the parking lot had endured a hole being ripped into a family. Each reunion would come only after years of pain.