I regularly volunteer in the textile department of our university museum. My work is sewing sleeves on quilts, most of which are far older than 85 years. Although no one quilt is hung in the museum for an extended period of time, when they are displayed, it is usually for a few months at a time. You say your church quilt is in excellent condition, so if it is not made from delicate fabrics, there should be no problem using a sleeve. In fact, that is the best solution.
FYI, when not displayed, the museum quilts I work with are rolled with archival paper on tubing, not folded. They are stored horizontally.
If the church treats the quilt with respect, as they probably do with banners and paraments, the members should be able to enjoy its beauty for many, many years.
P.S. Veinurse, I grew up on a farm about 100 miles from Fargo. I will be back in January to visit my mother in West Fargo.