I have always found it easiest to add the borders before quilting. I hope once the quilt is pieced, you can post a photo and we can help give suggestion on how to simply stitch in the ditch. As mentioned before, check your batting instruction to how close you have to stitch. That is to prevent from the batting wadding up with in the quilt. It is so nice of you to help this family make a memory quilt. Domestic violence is such a sad affair.