I've read this before. I think it was shared by someone else. It's possible he does. He may just have a vindictive side to him. There are plenty of people like that that will just take pleasure in exploiting a weakness. But if she truly is having serious conversations with him about it and he continues to do it, then I agree with the advice to consider breaking up with him. I disagree that simply saying "please don't tickle me" being enough because that's a natural response. 90% of us fetishist respond that way and will actually make it sound convincing. But if she is actually having conversations and he continues... she should definitely consider leaving him. If something like this is ignored, there's no telling what else he will ignore and he will, likely, only learn by her taking proper action.
Or... the fetishist in me could just say to tie him up and give him a good long dose of his own medicine....
Sent from my SM-N960U using Tapatalk