Can an infant's cord blood be used to cure or treat type 1 diabetes in the mother?

NO. At this point this type of treatment is only active in the laboratory. Meaning it has not been tried on a wide scale level in human patients and is not fda approved at this time.
See below. There is a very small study (15 patients) saying that there seemed to be a decrease in the level of diabetes after "stem cell educating". A cure? Not at this time. However, if you have the financial ability this might be a good time to save the cord blood and placenta of the next child, just in case.