Before the shocking news of his sister broke, Louis was promoting new music that was about to be released, which came with various interviews.
In one, he discussed how disappointed he was in former band-mate Zayn Malik when he didn't come to support him during his X Factor performance following his mother's death.
"I had a couple of calls with him after I lost my mum and all the boys had agreed to come to that performance and he didn't show, so that really bugged me."
Zayn didn't respond to the jab immediately, but after the death of Louis' sister, Zayn posted an apology in a now-deleted tweet.
"I'd like to apologize for basically being a sh*t person," he wrote.
Louis has yet to make any public comments regarding the recent tragedy in his family, but maybe, just maybe, Zayn has privately reached out to him during this heartbreaking time.