Not sure if it’s exactly what you’re looking for, but adding this to Jetpack’s Custom CSS (or your child theme, or whatever you’re editing in) should move the link down there with the rest of the meta info.
#content .post { position: relative; }
#content .comments-link { position: absolute; bottom: 1em; text-align: right; }
#content .post { padding-bottom: 3em; }