Bridal Shower Etiquette

I thought that it was not proper for the bride`s mother to throw her daughter`s bridal shower, true? Also how close to the shower do you send the invitations, I thought no sooner than 3 weeks since everyone is local and are co-workers. My friend`s mother from out-of-state is throwing her shower (not letting any of her friends do it) and I was asked to get the addresses together for her. She insists that I send the invitations months in advance besides the fact that the shower is nearly four months prior to the wedding and right before christmas. HELP