This is starting to sound very familar..... my mother slipped a disc whill she was lifting a lady out of a bath in a rest home, when she was 27 (now 52). Because it was her job... she had to carry on or leave the job. She was on around 12 co-proxamol every day for 10 yrs, and still has problems. She left shortly after damaging her back and went into a different line of work.
Your sisters employer doesn't want someone who can't do the work. I can see both sides, point of view.
You sister needs to get out of that environment - it is only going to get worse - if she stays.
She REALLY neads to take care when bending, as I said before. And she could do with going to pilates and strenghtening the muscles that keep the discs in place ie core strength training. You see what happens is the injury weakens the muscles so it is more likley to happen again... then you a so careful with that part of your back (dont do anything, for fear of pain) that they become even weaker and it is a downward spiral... Urge you sister to get involved in some supervised excersise - Yoga is good too.
You mentioned that she is waiting to see an osteopath.... is this NHS? if so, she could be waiting ages. If anyone of you can afford it, I would urge your sister to get seen by a very good private osteopath. OK it might cost £150 or so for the nessecary appointments, but on the other hand she could still have problems 25yrs later like my mother - who went the NHS route.
If you nedd help tracking a good osteopath in her area, I can probably help you out.
And don't forget the proper way to 'bend'. And as i'm sure she is doing - sit wherever she can (as this will take the pressure off the discs) eg. get a high stool to wash up, iron, make the evening sandwiches etc etc!
I notice from another of your threads that your Sister is pregnant..... This could well be the source of the pain. The old injury has become aggrivated by the spine being slowley out of shape. This may settle after a short time. BUt it may not. She needs to see that osteopath ASAP. And tell them the whole story.....
And yes it is perfectly safe to give Reki from the first day to the birth itself - Reiki can do no harm (except on un-set broken bones of course!), and Reiki babies are so very special. Good luck. And never spare the Reiki with your sister.
Love and Light
Saffron