Appearing on The Dan Wootton Interview podcast, Louis revealed that things got bad between him and Zayn after he didn't show up to his emotional The X Factor performance days after his mother Johannah Deakin's death in December 2016.
"Truthfully it never really got better," Louis said.
"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."
He added: "It was just seeing everyone there – Harry, Niall and Liam – that was what I needed that night, that support.
"So on the other end of the spectrum it kind of really showed. So, eh, I hope he's alright, but..."