Hi,
As his PSA level is normal; that means he is now facing "benign prostatic adenoma", which are causing such problems to your father.
Usually, doctors will evaluate the current health condition of your father if he is eligible to surgery or not.
I would suggest to talk to his
urologist for any probable urine infection as it is associated with
BPH. For this, can do urine analysis and urine culture to exclude infection or to get the best treatment with antibiotics.
Next, to ease his burning sensation, some alkalinizer salts can be used, including potassium & zinc citrates. Furthermore, many herbal teas for
prostate can be used to ease and shrink prostate.
I often suggest uva ursi mixed herbal tea; while saw palmetto is also effective or any other local herbal cure.
Hope it helped!