Papillary urothelium carcinoma. Grade?

My father is 57 yrs old. He underwent rigid cystoscopy and Turbt 28days ago.dr found a 2cm superficial pedunculated papillary tumour 1cm away from left UO and another small 0.5cm papillary lesion right side proximal to right. Dr.gave immediate intravesical mitomycin 40 during Turbt.Deep muscle biopsy taken.His biopsy report shows that it's a G2 low grade papillary urothelium carcinoma.definite subepithelial connective tissue(lamina propria) invasion is not seen.deep muscle (detrusor muscle) isn't identified.perineural invasion is not identified.Definite lymphovascular is not identified.comments-severe cautery artefact limits definite comment on invasion.Now the doctor is giving mitomycin 40 weekly for 6weeks and then advised for cystoscopic surveillance.Is he following the right procedure?Why he is giving mitomycin 40 instead of bcg? The grade is 2 but he explained it as low grade?