I've never experienced having a vet try to "make" our cats pee. When Pippin had his bladder infection and crystals, they had me leave him there all day so they could get a sample the regular way. He was so uncomfortable from the infection - acted just like your Bobo - that he just paced around for about a day after starting the antibiotics and then finally started getting some relief.
Our vet also mentioned adding Cosequin to Pippin's diet - she said studies showed that it might help strengthen the cells that line the bladder so it can resist infections. That was 6 months ago and he has not had a problem since. The rest of the boys get Cosequin too. Whatever works, I guess.
Hope Bobo gets better soon.