Pressure cooking does make it a little softer. Not sure if it would help that much. If it is a size issue, perhaps pulse the cooked meat a few times in a food processor until it is finely ground but not paste.
If you want to spy on my food blog, you can find it here: Palatable Pastime
Try the cheaper, fattier ground beef. 73% lean, maybe. The extra fat will give it a softer, juicier mouth, and it will stay moister, easier to swallow. Tastier, too, if you're OK with a little more animal fat in your diet.