Are you looking for someting to keep him from falling out of bed or as a grab handle to get in and out of bed? I used the under the bed type for my mom whose about 160 lbs and it works great as a grab rail for her. They are cheap and easy to install. It might work for a 195 lb man if he is still somewhat ambulatory and/or has assistance.
The one we have has a strap that goes around the box spring to keep it in place, it's very secure. I think it also would make a difference which kind of mattress you have, a 6" lightweight foam is not going to support it as well as a heavy 10 " coil.
My Dad had also used an under the bed type rail which he needed to help him sit up and stand. He was quite happy with that rail. But every week I did have to push the rail back toward the mattress as Dad would eventually work it away from the mattress.