Thank you for posting your query at Doctorspring.
The fistulous tract will be connecting the external and the internal opening.In fistulectomy,the whole tract will be excised.It will be left open without suturing.
After operation,he has to do Sitz bath with Betadine solution.Slowly,the wound heals.
He has to take antibiotics to prevent infection.
He can attend his normal work after 1 week of surgery.But,it may take 4-6 weeks for complete healing.
He should take high fiber diet.
Hope this helps, please feel free to discuss further.
Wish him speedy recovery.