I would probably not use a fusible on an old quilt like this unless it was used very judiciously -- MistyFuse and even then only underneath existing patches to close up a tear.
For patches that have more than just a tear, I would hand applique fabric on top (with turned under seam allowances). I think that is the most common technique for repairing old quilts.
For historical preservation of important quilts, the restorer usually just hand sews a protective cover of fine tulle over the damaged pieces.