Deat Doctor, My Father In Law Aged 68 Has Difficulty

Deat doctor, My father in law aged 68 has difficulty in passing urine. Scanning indicates that prostate is enlarged 4.7 * 4.5 * 4.2 CMS - vol 46 cc, post void residual urine 132 cc. Moderate prostatomegaly with significant post void residual urine. Prostate enlarged in size and normal architecture. He had undergone kidney stone operation two yrs ago. Kindly advice.