You DH and son looked as if they had a great time taking your Brother apart.
When I began quilting 11 years ago I bought an inexpensive Brother at Costco for about $150 and sewed so many quilts on it that I had to have it serviced every year. When I realized that I had spent more for servicing than it's orginal price I began looking for a better machine. Other problems were that the vertical thread spindle broke off and couldn't be replaced and then the upright plug in spindle broke off so I had to use a glass to hold the thread spools. Little old Brother is still around, even got a thread holder for it. I use him for pillowcase sew ins, since I'm one of the coordintor of my Guild's pillowcase project I sew a lot of pillowcases a year.