I'm 35, male with OAB which manifests mostly with bedwetting and daytime urgency with occasional daytime leaks. After Kegels didn't prove effective, oxybutynin was the first drug the doctor tried. I took it for maybe a week. The side effects were unbearable for me (crazy dry mouth and headaches). We tried Detrol and Toviaz after that. Same problem. Now on Myrbetriq. The side effects are much lower so far but I've only been on it about 5 days. We'll see how effective it is. I'm still wetting the bed every night and still having urgency during the day.
If this doesn't work, I'm taking a break from pills. I can live with wearing a diaper to bed, really and pull up style absorbent underwear during the day. I wake up dry and have no side effects.
Is your husband wearing diapers? I'm sorry to say but from what I've read (and I've read volumes) since my problems started, as many as 70% of people quit anticholinergic/antimuscarinic meds within a year because of side effects or unsatisfactory results. Many with incontinence end up relying on diapers. Don't get discouraged though. These drugs work wonders for some people. Sometimes a combo of drugs, kegels, behavioral stuff and absorbent products can get people back to a quite normal life.
If he's really averse to wearing a diaper long term, he could try condom catheters. Last resort could also be surgical urinary diversion where they re-route the urine out of the body through a stoma and into a collection bag. Personally, I'd rather wear a diaper than go under the knife but everyone's different.
Does he have access to a continence nurse or counselor?