I don't think ivermectin & fenben are going to work for this.
He tried that for like a month and when he didn't see immediate results he rage quit and called it a hoax.
It wasn’t even a month. He gave it about a week or two and dropped it because he didn’t like the man who was guiding his treatment. That man (I forget who it was) said it can take up to 3 months to see noticeable results. It’s not a magic spell.
I'm sure that he will be fine.
Keep on trusting the science.