I'm afraid the only way to solve that problem is to cut the top off and send it to me. Haha but seriously, the basals look fine, but the main vine does not. Often, when there are multiple basals, it drains the energy from the main vine which eventually dies (though the basals will live on. So if I were you I'd either take a cutting or separate a basal or two. Conversely, you could try to spray the plant with 50-100 ppm GA3 to halt leaf senescence. That probably won't help the plant in the long term, as I'm sure you'd have to do it a couple of times, and it might not even solve the problem w/ the main vine.