Thanks, everyone! He is going to the framer on Thursday.
And yes - I feel pretty confident about french knots now!
Also going to the framer is another tapestry of my mother's. One of my family members had it, but instead of hanging it, it was stuck in the attic. Although framed, it was without glass, and in the attic it got a bit motheaten, as well as very dusty, and the frame got broken. The family member returned it to me optimistically thinking I could fix it.

Anyway. I took it out of the frame - with some difficulty. Whoever had framed it for my mom had trimmed it to within one eighth of an inch of the stitching, and fixed it the back panel with drawing pins and glue.

Sheesh! So... washed it, found some of mom's yarn (I kept all her yarns) that pretty well matched (though it was a bit thicker than the yarn in the tapestry) and filled in the motheaten bits. Asked my framer if he was up for a challenge; explained; and, bless him! he said yes!
The tapestry is probably the first my mom did, and she designed it herself, taking Egyptian motifs, and got a friend to draw it onto the canvas for her. I remember her stitching it, so I had to try to rescue it.