My dad's prostate 58gms. PSA 5.8. Urine retention 200 ml. No irritation etc. While urinating. Should he go for surgery or medicinal cure?

Meds first. Hi, It is good to try medication first.Alpha blockers(eg:tamsulosin)work within hours,5-alpha reductase inhibitors(eg:finasteride)take up to 6 months to shrink the gland but they do work.Also I suggest a combination of both which is available in same pill here & probably in India too.If meds no help,next option TURP or laser. Best wishes for your dad.
Medical rx . Given the scenario I would first get a prostate biopsy to rule out prostate cancer given his PSA is elevated . If that is negative I would favor medical management initially .