Fixing wet "f" sounds in Audition

Hi, I am editing an audio book for a client. He has a tendency to make very wet sounding "f" sounds which come up as sounding long and spluttery... like ffffftfftftftftfffftt. I'm trying  to selectively chop the sound. Sometimes it works, sometimes it doesn't. Have tried auto heal but it sounds dull and woofy.

I have also tried the FFT filter but can't find a way to make a difference with that particular sound.

Does anyone have a suggestion?

I've attached a couple of quick grabs. Thanks