McLeod revealed that his brother-in-law was now "doing ok", but the surprise battle was "fresh" for his sister.
The Sydney-based reality star said he was doing his best to support Rachael in her time of need.
"I'm just trying to just be there for her. All our family is really close and supportive and we're lucky to have that," he said.
"I've got two other brothers as well and when you go through times like that you kind of rally together and help each other out and just keep spending time with each other."
"Love is the most important thing. It conquers all - I know that sounds a bit cheesy but if you put everything aside, everybody goes through ups and downs and has fights and so forth. If you just come back to love, it's all good," he said.