Yeah.. That sounds like a rather shitty situation. I am addicted to benzos, and wouldn't think of stopping.. but also would never recommend taking them to anyone on a regular daily/nightly basis. It is probably one of the worst, if not the worst addiction one can possibly have IF they are forced to abruptly stop taking benzos, of any kind after taking them for enough time and at high enough doses to become addicted.
Switching your dad, from z-drugs, for sleep to a benzo like Ativan or lorazepam, as well as alprazolam too, is just uncalled for! Why not just keep him on what seemed to work for him, and isn't nearly as addictive and dangerous to discontinue usage?! And the fact that you said the doc who gave him the lorazepam was old, is kind of scary... I don't think I could ever feel comfortable at the stage of benzo dependency I am at now, having taken anywhere from 3-5mg a day of clonazepam, everyday (prescribed) for the past 5 years... I would be absolutely terrified of having to find a new doctor, if mine just died! never really though about that before because my doc is a middle aged woman.. in her early 40s I would say? and I have such crippling anxiety both general and social, and insomnia... tried every other alternative such as SSRIs, sleep aids both prescription and OTC, and numerous other things before just giving up, and realizing I have such terrible anxiety, even WITH the klonopin, that I just wont be happy any other way... I am so happy, and everything is well, no panic attacks, no worrying over nothing, and no more sleepless nights as long as I have my meds, klonopin that is... when or if I ever run out too early, which has happened a few times... it is the worst possible feeling, I have ever felt!
So... I would indeed, before your dad is hopelessly addicted to benzos and to the point of either having to suffer through heinous WDs to get off benzos or has to stay on them his whole life, which does happen... its happening to me right now, I wouldn't think of trying to get off of them... you should see if there is another doctor that would prescribe him something actually, specifically meant for JUST sleep.. like zolipedem which you mentioned he was previously on, before lorazepam/alprazolam came into the picture, which is for mainly, anxiey/panic disorder and insomnia, not usually just insomnia..
Seriously hope you can safely taper your father off of benzos, before shit hits the fan! I wouldn't wish it upon anyone! Its a terror of a withdrawl, even for just a day or two to go without mine! I cant for the life of me, understand why some doctors make the weirdest, stupidest decisions for their patients... that doctor who had your dad on z-drugs for sleep, had it right before abruptly just saying "no more for you!" basically, and ripping him off of them, forcing your dad to see someone else, who though benzos would be a "safer" better idea... phhhh. some doctors are just ridiculous! Best of luck to you and your dad!