Rob made headlines last month when he skipped sister Kim's wedding in Florence, Italy, choosing to fly home to Los Angeles on the day she exchanged vows with Kanye West.
Rumours surfaced of a possible family row and that Rob was unhappy about his recent weight gain being shown on wedding pictures.
Doing the publicity rounds yesterday, his mum Kris didn't deny those rumours but also refused to specify what Rob is going through.
When asked on the Today show if she'd feel comfortable discussing it, she replied: "Probably not. Rob is working on himself. He's going to be okay. He's such a great human being and such a nice boy. He's my heart."
Kris later told E! News: "Rob is living in LA right now and doing well. He's finding out what makes him tick and struggling with some stuff. My job is to be there for him and love him as hard as I can."
She added: "Everybody goes through stuff."
Rob made headlines last month when he flew out to Paris, France for Kim and Kanye's week of pre-wedding celebrations, as he'd been out of the limelight for a while.
His weight gain became a trending topic on Twitter and he eventually spoke out to deny rumours he'd enrolled in 'fat camp' to help battle the bulge.
"So I found out I was trending for being fat," he tweeted. "Thank you all. It really made my day. To the blogs saying I went to fat camp or rehab. LOL. Then why am I still fat you fools? Y'all must have run out of real news."
He concluded: "First, I don't believe in rehab or therapy or anything of that sort, and second, I'm a grown man and will work on myself when I choose. I'm aware that I'm fat that def aint a surprise to me lol and my only therapy will be in the gym anyways had to say somethingggggggggg."
This week, it was confirmed Rob has enlisted the help of celebrity trainer Gunnar Peterson to devise a workout regime to help him get back in shape.
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