Hello Doctor, My Brother Has Severe Pain In His Lower

Hello Doctor, my brother has severe pain in his lower lower abdomen. we consulted physician and we thought it might be because of food poisoning. after getting Ultrasound report, that shows A right lower ureteric calculus app. 5.7mm in size is noted with the proximal Hydroureteronephrosis.
kindly suggest, is it dissolving or not & what is the treatment for the same.

Thanks & regards,
Sapna