Ask her if she could video herself working on it, so you can know that it works. 43,000 stitches is not a large number for a machine used for FMQ. The table, and so on, seem right. I think you could use facebook live for the video, so you know it is not an old video or someone elses video.
I bought a HQ16 used, with frame, table and pc quilter in 2010 for $4,000. It has worked very well; most problems I had were due to operator error. My sister has the table, so it was never used by either of us on the table. It does not have tru-stitch, so can't speak for how well that works.
My DH cleans the machine for me about every 2 years, and so far we have found nothing to complain about before or after cleaning. The needle area always has some fuzz in it, even though I do take the needle plate off now and then to dust it, but the rest of the machine is clean and lint free. I oil clean and oil the bobbin area after each quilt is done. So maintenance has not been a problem for me.
If you can see the machine work, are able to look at whatever is quilted, and you really want it, I say go for it.
On another note, Grace Company now has a mid arm quilter, the Qnique. (Grace also makes the Block Rocket, which is the identical machine to qnique: although Brother is the actual manufacturer of both of the machines and has it's own Brother branded machine as well. It comes in 15M, R (which I think means stitch regulated) and a 21 inch. I believe you can get a new 14+ and a table for about the same cost as the used HQ set up. I am considering upgrading to the qnique 21 on a frame, and am this close () to making the purchase. My HQ set up will go to my sister, as she quilts as well.
An intensive search on Qnique to find best prices and dealers before you buy the used HQ. Having said all that, I have NOT ever actually seen a qnique in use, so everything I know about it is what I read on the internet.