My husband's 27 year old daughter (my step daughter) is planning her wedding and seems to think that the 'father of the bride" is to pay for everything (with her mother contributing no financial assistance). Is this etiquette or manipulation? Doesn't "parents" of the bride imply a split of expenses?

There is no hard and fast rule to who pays. It in not the obliqation of the father to pay for everything. If the parents of the couple can and would like to pay they can. At 27 I would think the marrying couple could pay for their wedding. Your husband if he chooses can pay what he would like. If he is going to help finacally he had better be very clear about the amount/what he will pay for.