John McCain's family celebrates his 81st birthday: 'You have kept me laughing for 37 years,' says wife Cindy

"You have kept me laughing for 37 years," tweeted wife Cindy McCain.

— -- Senator John McCain's family inundated their social media accounts Tuesday with birthday greetings for the Arizona Republican lawmaker, who turned 81.

"Thank you for all the birthday messages! It's been wonderful celebrating with family in #Arizona doing the things we love most," tweeted Sen. McCain. Along with the tweet were photos of him hiking, blowing out birthday candles, barbecuing, and with wife Cindy and daughter Meghan.

McCain recently finished the first round of chemotherapy and radiation treatment at the Mayo Clinic in Phoenix for brain cancer. He is slated to return to the nation's capital following the August recess.

A day before his birthday, Cindy McCain posted to Instagram the photo of her husband blowing out birthday candles. "An early 81st birthday! Happy Birthday to my love! @senjohnmccain," she wrote.

"Happy Birthday to my wonderful husband @SenJohnMcCain," tweeted Cindy McCain on Tuesday, with an image of a beach with hearts carved into the sand. "You have kept me laughing for 37 years."

Meghan McCain, 32, tweeted, "Everyone help me wish my wonderful father @SenJohnMcCain a very happy birthday! I love you with all my heart, Dad!"

Sen. McCain also posted a birthday greeting video, writing, "Thank you to our Iranian American friends from #Arizona for the birthday wishes!"