BPH or something serious? Else?

My father (Age 68, diabetic) was diagnosed with "Enlarged prostate with coarse echotexture"(35 cc residual urine) in 2019. He took "Maxvoid Plus 8" for 6 months & had another ultrasound in 2020, which said prostate is normal is size with homogeneous echotexture. After that doctor didn't prescribe to continue the BPH medication & he stopped taking Maxvoid Plus. Now from the last few days, he was having fever, chills, frequent urination, blood in urine, painful urination & lower back pain. Urine culture says no growth was found. After taking Gericef 500 for 5 days, fever & chills gone but urinary symptoms are still there. The latest USG report says - 1) Grade 2 Prostatomegaly with heterogeneous echotexture. 2) Thickened, irregular, trabeculated UB wall; features of bladder outlet obstruction (70cc residual urine found) Is it due to BPH or something else? Kindly suggest.