hello and welcome to HCM,
I can understand that many people do not like to visit doctors for different reasons but believe me when it is required then you must visit so that you have a relief in one way or the other.
In your dads case since the eyes and face have got swollen to such a large extent we really do not have much choice but to advice him to consult an ENT doctor as soon as possible so that he can recommend a proper treatment which can go in these lines:
1. An endoscopic examination of the nose and paranasal sinuses
to point out the severity and extent of the lesion
2. A CT scan
of the nose for the same reason with more emphasis on the state of the eyes or the orbit.
3. In all probability you must remember that though his life may not be at danger it is always safe to get the treatment started as earlier as possible so that you will have a better and much faster recovery.
take steam inhalation, continue antibiotics and anti-inflammatory
get well soon
Dr Sriram Nathan