Hi Willow,
Child Birth International and Optimum birth offer courses online in training to be a doula, I am going with CBI as I feel they have more to offer in line with what my objectives are.
I think that having the option of studying from home is great for SAHM as it can be worked around a hectic shedule and you have 3yrs to complete it.
Worth looking into and if your friend decides to do it she will find your support invaluable.