Hope you feel better. Here is a link to a couple of presentations on MDS - the two at the bottom by Dr. Gail Roboz might be especially helpful - on general thoughts and practices - and on new treatments on the horizon. They are long but very informative and clearly presented.
https://www.pathlms.com/aamdsif/searches
It looks like you are in New Brunswick Canada? If so, I suspect you doctors are not especially experts with MDS as it is not all that common and it manifests in many ways. You want to find someone who has some experience but who isn't afraid to admit when they don't have an answer - but someone you and your mother feel comfortable with - and who will find out the answers to questions you don't know. The nearest MDS center to you that I'm familiar with is the Dana Farber Center in Boston.
http://www.dana-farber.org
It may be too far to travel to - but perhaps you or your doctor can get a telephone consult. A transplant is not an easy thing and you mother may not want one - but if you do go in that direction I think its important to go to a center that is on the cutting edge if you can - transplant technology and protocols are changing rapidly.
That said, it sounds like the Vidaza is working and as long as it works that's great - While it isn't a cure, it can work for a while and as long as it works enjoy those days.
Did they do any genetic studies when they biopsied your Mom? There are some chromosomal anomalies that correlate with better or worse outcomes - and that might influence treatment options.
I am 55 and was diagnosed with low risk MDS 2.5 years ago. I recently started Vidaza with the hope it will work for a while - if not a transplant may be in my future. if you have questions you'd prefer to send via private message that'd be fine - if I can figure out how that works.
All the best,
P