What Is Pilonidal Sinus?

hi doctor, my husband is suffering from pilonidal sinus...he is 29...he has a small hole in the cleavage at the back between his buttocks and next to the hole there is a boil with pus. doctors gave him antibioctics n he is much better...my doctor suggested..he might have to go for a minor surgery.....i would like to ask you if this is curable with antibiotics and medicines or he has to go for a surgery?...if thru antibiotics...will the hole disappear or still remain??thank you