"It's very hard. Yeah, I still miss her very much. I tear up fast," WWII vet and retired mailman Krueger told KFYR-TV.
LaVina Krueger had wanted to throw her husband a 90th birthday party.
Since she didn't get to, Debra Turner, one of Harold's daughters, decided to intervene and try to make his day special.
"My dad served in three wars, participated in the evacuation of Chaing Kai-Shek from China, was sent to Cuba during the Cuban missile crisis, served in the secret service under Richard Nixon, and was a mailman at the Grand Forks Air Force Base for 14 years. He received the Purple Heart in Korea," she posted on Facebook.
"This man never complains and has truly put family, God, and country first. Since the passing of his best friend and wife, the highlight of his day is going up to the post office to get his mail. As you can imagine, most of his mail is bills. My dad does not have internet. On Feb. 21st he will be 90 years old! I am asking you to please send him a card, a note, a letter, thanking him for his service to this country and wishing him a happy birthday. Imagine how thrilled he will be to receive actual mail!!"
"Maybe if I put it on Facebook, and ask some of my friends if they would send my dad a card he might get a few letters and some mail. So, I gave a little background of his military, and his life and asked. That's all I meant was for him to have a couple letters," Turner told KFYR-TV.
Her plea was shared more than 750 times.
Last week, in time for his birthday on Friday, Krueger received more than 700 letters and cards from strangers all over the United States and Canada. Some envelopes arrived from schools, stuffed with birthday wishes from young students.
"The kids, it's fun to read whose those little kids say because their words are from the heart," said Krueger.
"Today's card and letter total 498! Plus 7 big packets of letters and cards from various schools. There were so many cute messages from kids. My choice today is, 'Good job saving the world!'" Turner wrote on Facebook.
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Some people sent birthday cards. Others thanked Kruger for his service to their country. Some soldiers even sent him gifts.
"He's receiving a large amount of mail — literally hands full a day, and I'm pleased to deliver it," said Wishek, North Dakota, postmaster Doris Bettenhausen.
Turner has been posting mail updates on Facebook:
"Having an accurate count for the mail my dad has received is difficult because I realized that early on when a bunch of letters came in one envelope I marked it as just one," she wrote. "I'm sure he is over 1000."
If you, too, would like to bless Harold Krueger, write to him here: P.O. Box 176, Wishek, ND 58495-0176.
(Photos from Debra Krueger's Facebook page)