Edelweiss,
I'm glad you got the ADs. Yes, AD's can alter OCD behavior with regards to ANY OCD action. It also has been shown to help dementia a bit as well.
Once she is on the AD, after about two weeks, she will communicate better and can be talked to about her hoarding and other OCD behaviors.
OCD is a SYMPTOM of a myraid of other illnesses of the mind. Usually it is depression or trauma. The symptom of OCD can be controlled, also, with an anti psychotic. I've seen it control OCD with very, very low doses of anti psychotics. I think you are on the right path with the med's, Edelweiss!
Also: Keep in mind that medications can be switched until she has the right one. If this one does not control some of her urges, just tell the doctor and he can try another. Again, at times it is an anti psychotic that controls this symptom.
OCD is a symptom as are other coping stratagies the mind has to block out the real illness. Is she likely depressed?
If she is healthy bodily, she needs to be looked into as far as psyche meds to level her thinking and help her to be happy. Remember, Edelweiss, she cannot help her OCD or depression, etc, it is a disease and there is medication for it. It's not uncommon and I run into a LOT of patients of her age on psyche meds.
There is a back lash about taking psyche meds that some people have, they think that means people are "crazy," or "out of control," but indeed, they are just sick and the SSRI AD's provide for more clear thinking.
Other coping skills besides OCD are all the "phobia's," and panic attacks, etc... Now panic is an illness unto itself though, called GAD, (Generalized Anxiety Disorder.)
Watch to see if she tries to replace her behavior after about two or three weeks and if so, to what. I suspect that if the dose is high enough and the AD is the right one, it will change her for the better straight off.
What AD did the doctor give you? Remember that she must take the med every day to have the effect that you and she need. Sometimes the elderly have issues with such medication.
There is a problem if your mother REFUSES medication, and many, such as myself, have mothers that do just that.
You say her mind is sound and that is great, she just needs a bit of stirring up in the serotonin way and she may be just fine.
Please keep me informed, there are other things to try before you try control.

Best to you, Edelweiss,

Dancer