My Husband Is 83 And Healthy. On The 17th, He

My husband is 83 and healthy. On the 17th, he had a systoscopy to check on his enlarge prostate. He is supposed to be scheduled for a procedure soon. He is urinating frequently and OK> For the last 2 days, his testicles and the whole sac have filled up with fluid, the sac is quite enlarged. Can this wait until tomorrow or should we go to ER. He has no pain, just an enlarged scrotum that seems filled with fluid.
Beth Cafagna YYYY@YYYY