Martin Jacobs and Jean Milgram are best friends — and more.

He’s 78. She’s 101. They’ve known each other for 20 years, have been living together as housemates and dear friends for more than 10 years, and have traveled around the world together.

“I’m like her son,” said Jacobs, who is now also Milgram’s full-time caretaker. He welcomed her into his San Francisco home in 2009, when both of them were living alone. “She said she was lonely” and he wanted to help her, providing companionship as well as assistance with the tasks of daily living.

They met in 1999 when he was just 55, and she was just 80. They were introduced by Jacobs’ mother, Bea, a close friend of Milgram’s through the San Francisco chapter of Hadassah. They connected almost instantly over their mutual interests, Jacobs says.

He collects patriotic World War II memorabilia and has written several books on the war. She was a “Victory Girl” during World War II, serving coffee and doughnuts and dancing with GIs at a military training base in Florida in the evening while her husband was in the Army. During the day she worked at the commissary.

“She told me stories about the troops. It was just great,” Jacobs recalls. “Jeannie inspired me.”

Born in Romania, Milgram fled the Nazis in 1939 with the help of an uncle who took her to France and got her on board a ship headed for America. Her mother perished at Auschwitz.

She was 17 and arrived in New York alone. “All the people that complain about living in America didn’t have to go through what I went through in Romania,” Milgram told J. in a 2002 interview. “If you were Jewish and lived in Romania during World War II, you wouldn’t have a chance to complain. From the moment I got here, I never once complained about living in America.”

She met and married Leopold Milgram in New York. In 1957 the couple moved to San Francisco, where she got a job as a bookkeeper at the I. Magnin department store. Milgram retired in 1985, the year her husband died. They had no children.

She didn’t sit idle. Milgram took up volunteering: running the gift shop at Kaiser Hospital, knitting blankets and beanies for infants, and assisting the San Francisco Food Bank, Seniors Plus and the JCC of San Francisco, along with her Hadassah activities. She wanted to travel but lacked a companion.

That’s how the two friends ended up seeing the world together. Jacobs says he began joining her on cruises, sailing to China, Japan, even Iwo Jima. “We took World War II cruises,” he says. “I would meet the veterans on the ship. Jeannie would go and talk to them, and wave me over.”

These excursions fit right in with Jacobs’ interest in wartime memorabilia. He has collected postcards, posters, stickers and decals from the war years. “My dad kicked it off by giving me his dog tags,” he says. Many years later, “Jeannie gave me her victory pin that she wore. That’s my prized item.”

In 2001, his book “V for Victory Collectibles” was published, and Milgram accompanied him for book signings aboard the USS Missouri, USS Bowfin and USS Arizona at Pearl Harbor.

An even greater passion, though, has been Jacobs’ lifelong obsession with the San Francisco 49ers. “At 9 years old I worked at Kezar picking up [stadium] cushions for a nickel apiece,” he says, referring to the football team’s first home. “At 14, I sold doughnuts and malts. At 20, I sold hot dogs.” In addition to earning some spending money, “I began collecting items that fans had left behind. I would go in the stands and look for sticker stubs, yearbooks.”

A 49ers “fan of the year” in 2000, Jacobs is something of a team historian. Earlier this year he published “The King,” a book about former 49ers running back and Hall of Famer Hugh McElhenny, whom Jacobs considers a friend. “Hugh influenced me in everything I did in my life and shaped my character,” Jacobs said. “My feeling was if McElhenny could escape tacklers like he did, anything was possible.”

As busy as he is, Jacobs’ first priority these days is his friend Jeannie, who is staying indoors during the Covid pandemic.

Milgram was diagnosed with terminal cancer about five years ago and given months to live. “Apparently she has an angel watching over her,” he says. “She refused any treatment and is just living her life to the fullest. In fact, she looks forward to an In-N-Out burger when her knitter friends stop by to visit.”

Hospice comes to the house to check on her, and although she is not nearly as mobile as she once was (“she was walking five miles a day at 80”), she is stable and her vitals are good, Jacobs says.

She loves Scrabble, reads a novel a week “and still has a great smile,” he says.