Try getting it completely wet (gentle wash). Then with friend or spouse (whomever you can get),lay it out flat (the floor is your best bet. I would use some of that laminated (?) shiny fabric (like the stuff you would use to cover a picnic table) to keep the quilt clean and the flat area dry. With your helper, carefully pull and smooth the quilt out, be careful that you do not pull the binding and get all out of wack. Let it dry for a few days; then turn over to dry the other side. You could again smooth it out at that time. I hope this works for you. HOWEVER...before going to all that trouble, take it to someone who knows about quilting and get their input. You may save your self a great deal of work and worry. No matter what, if your MIL loves you, she will love the quilt. That, however, would be your call.