He now has 13.5million subscribers – previously the figure was about 16million, according to the website Social Blade.
It comes in a week where the 19-year-old has denied using his fame and money to try to manipulate men’s sexuality.
Meanwhile, his row with Westbrook centres around him promoting a rival product to one she’d created.
Westbrook and Charles have both amassed enormous social media followings through make-up tutorials and beauty product reviews.
He says the 37-year-old took on a “parental” role after they met three years ago.
However in a video titled BYE SISTER, Westbrook said she was cutting all ties with him.
“When you paired up with my number one competitor it was embarrassing for me and you know that.
“You kept saying you can’t be bought, but you just were,” she said.
As well as accusing him of being disloyal to their friendship, Westbrook also claimed Charles tried to “manipulate” people’s sexuality.
She said the teenager would regularly boast about wanting to turn straight men gay.
She said: “You are using your fame, power and money to play with people’s emotions.
“I don’t want to be friends with you. I don’t want to be associated with you.”
More than 39 million people have watched the video since it was uploaded on 10 May.
Following the release of Westbrook’s video, Charles posted a video on his own channel.
Simply called Tati, he apologised for “everything that I put you through”.
“What sucks the most is that I know there’s nothing I can say or do to ever earn that friendship or trust back, but I don’t blame them for it.
“A lot of the time when I’ve had to address things in the past, I’ve acted out of impulse and I’ve gone off and tried to pull receipts or facts or screenshots and play the victim.
“I’m not doing that today, I’m not. That is all I have to say, I’m sorry.”
The 19-year-old however denied he’d ever pressured someone into dating him but conceded he’d perhaps mishandled situations in the past.
He said: “I’ve been involved in a lot of very unique situations that have left people confused or upset.
“I have learned the hard way about boys that I am interested in, and also ones that I should or shouldn’t be talking to.
“This is a conversation I know a lot of people are uncomfortable with and it’s something that I should have been far more careful with bringing into the public, especially with the last situation,” Charles said in the video.
Credit: BBC News