It's called a hookah, and I don't see how it would impact the risk in any way.
It just popped into my mind because as Charlie99 said, it would act as a tether and if I remember correctly, it is usually done in very shallow water.
Extra precautions like a full face mask & an attentive buddy(ies) both keeping an eye and sharing the experience would help.
It won't be SCUBA, but if she really wants a taste of the experience, I sure more knowledgeable people could fashion something around something like this.