GG,
Adding on a welcome to you. The doctor may suspect MS, and may be able to correlate a few things for the criteria based on initial suspicion, however much will need to be investigated in order to know if you truly have MS. In addition to the MRIs, a battery of labs should have been ordered as well.
I think you will find this write up informative because it speaks to what MS is, and what it is not.
http://www.medhelp.org/posts/Multiple-Sclerosis/MS-and-References-to-DX-of-Exclusion/show/1602461?controller=posts&action=show&id=#
As to meds to treat the disease. As mentioned above, the original traditional meds, Copaxone, Rebif, Avonex, Betaseron are not immune suppressants - they are immune modulators. However, when on an interferon, there is a potential to have changes in blood counts. So, you are monitored. Not copaxone - it's a peptide.
I have to make a correction here to what's been said in reference to your Mom - No one can know that it's possible your Mom has MS. Please know a numb foot does not rise to the level of concern for MS. Don't want you to worry :)
Also, the McDonald Criteria does not state that there has be a steady progression for dx.
If you would like to learn more about the dxing MS, and the criteria - our health pages are jammed with good information. You can find them toward the right of your screen.
Thanks for joining us again, and hope we can help.
-Shell