Since May, Donna Van Schwarz has suffered several strokes, a brain bleed and had open heart surgery, the television station reported.
She now uses a wheelchair, but that has not dampened their love for one another.
"It just continues to grow stronger," Christina Von Schwarz told WFAA.
That was apparent when Karl Von Schwarz promised to buy that engagement ring. Once Donna Von Schwarz was healthy enough to go home, she told her husband to make good on his promise.
"She definitely didn't forget about that ring," Christina Von Schwarz told the television station.
So, the couple went to a department store and Donna Von Schwarz picked out her ring.
Urged by family members to make the re-engagement official, Karl Von Schwarz got on one knee in the store and asked his wife to marry him again.
She said yes.
Christina Von Schwarz posted a video of her grandparents on Twitter, and within days the post had received more than 25,000 likes, WFAA reported.
"I told them that they were famous on Twitter and they were so happy," Christina Von Schwarz said. "I never thought it would blow up, but it definitely deserves the recognition that it got."
Karl Von Schwarz told WFAA by phone that it was easy to renew his vows.
"It was great because it's a gal that I've loved all of my life," he told the television station. "It was very easy. You know, we've been together so long that we can't stay apart really."
"It's really beautiful," Donna Van Schwarz said with a laugh. "It's gorgeous."