Thank you everyone for the suggestion on how to fix this for her. The fabric is not frayed so that is why I believe it is a thread problem. I'm always pulling a thread so it may be that I pulled a small piece out. Will get some steam a seam and get that baby fixed. Hopefully she won't find any other problems with this one. This is the first time I've ever had this problem. Used all of the spool of thread so can't test it.
Again thanks,