I posted but my post got lost - dunno why.
Lisa, your husband will need progressive heavy weights in fewer reps and fewer sets. It is imperative that he rest between sets for one full minute for maximum results and muscle recovery. It's always a good idea to start with large muscle groups.
For toning, strength and weight loss, you will need lighter weights, more reps and more sets. You will benefit more and have more stable joints because you can vary the angle and get a more complete workout when you're training with lighter weights and more reps (a la Jack LaLane).
Machines lend themselves to aiding your body with its balance and you don't really have to use the smaller muscles and side striations of your muscles for balance of the load. Free weights force you to use these things TO balance and control your load. That is essentially the philosophy as I understand it.
Progressive resistance machines like Bowflex contradict how your muscles are designed to work. The majority of the resistance is met at the end of the flex. This CAN induce a strain injury.
The best thing I've seen for home use is the total gym. It operates on a Pilates based philosophy and is pretty easy to use. That and a few variations on light hand-held weights for you would probably do the trick you're looking for.
I SERIOUSLY recommend getting an eval and training plan from a pro. If you guys join a gym in the area, usually most of them (at least in the states) include one free eval, consult and workout session with a personal trainer. Talk to a nutritionist about appropriate sports nutrition that is food-based, unless you really WANT to drink those shakes. I avoid creatine (you're a nurse, you know why) and protein shakes and work on eating right for weight-lifting fitness when I'm lifting.
Post your progress when you can.