after tooth extraction often occurs when local germs infect the opening after the extraction. If after taking penicillin your husband is still draining ( antibiotic for 10 -14 days is much appropriate), you have to continue the antibiotics for 10-14 days and if the pus is still coming out, then your doctor will need to include another type of antibiotics to cover atypical germs. Continuous daily drainage
of the abscess is important for proper healing. It is normal he still feels sick if there still the um abscess/drainage. Systemic infection of blood stream (complication) is possible if antibiotics are not taken appropriately. A doctor will have to be seen soonest.
But if you see that there is an amelioration with the penicillin just continue.
Hope this helps