Hi Janice,
As one who started with none, then 1-2 pound weights and can now exceed the weights Cathe uses in her videos (but not while looking cute and talking at the same time

), I can tell you that even doing FIRM videos with little or no weight can be INFINITELY beneficial!
When I first started lifting, I could barely get through Kathy Smith's 20 minute sections of "Lift Weights to Lose Weight," on alternate days, with no weight at all, doing just the motions. It was, both physically and psychologically, all I could do to even attempt it. If I had thought I had to do it with actual dumbbells, I'd have been so overwhelmed, I might never have progressed. I couldn't even do the lunges with NO weight. I had to use a broomstick for balance and to help me get back up. It was well over a year before I could do the lunges without the broomstick. Another year after that before I could do them with weights.
I had to spend weeks, maybe months (can't remember for sure), just working my way UP to half a FIRM video! The first time I attempted one, I knew immediately that it was FAR beyond my abilities. Not that I gave up on doing it. I just knew it would be a while. It was. But I DID do it. And much, much more. New challenges have a way of hanging there at the back of your mind, even if reality slaps you in the face.
I don't know what kind of shape your friend is in, but I don't think I'd push her. You can't GIVE her the determination to do this. She'll have to come up with that herself. And if you try to move her ahead too fast, she may give it up. I know I pushed myself much harder than anyone else could have pushed me, but there was a definite limit to what I was capable of, and those boundaries were both physical and (as someone who had never formally exercised before at all) mental, as well. I'd let her find her own pace.
Just my $.02.
Shari