Go for it.
If I had a friend like that and she was willing to back me like that I would jump at it. My wife would be a little bit more cautious and tell to find out what she wanted first. I would tell her not to worry and I would handle it. LoL.
This appears a generous offer Denise and you should just ask them what they want in return from potential sales. You definitely have the talent and the portfolio to cover such an investment by a friend. All you need is a "break."
And this appears to be it.
Even with friends it is best to record on paper what liabilities each party are up for initially and the liabilities and benefits from subsequent sales.
On a personal level, this is something that was probably not on your radar and the benefit from exposure and marketing for your art will be a priceless investment in your future.
It may be best to limit the input and investment of your friend to this one showing and see how it goes. No loose ends at the conclusion, perhaps handover whatever are an appropriate amount of prints that do not sell to him to cover his expenses.
A lot of things to consider, but definitely a worthwhile endeavour.