Considering that the next chapter is the second to last and supposed to be the largest, the high point of most plotlines, the peak overall and starting to resolve everything for the final chapter and epilogue, it makes sense that this takes the longest time to develop. It also abstains from splitting, so it would take longer than if its just released on one earlier half. I'd give him some slack. In exactly three months we are one year from full chapter 7, if there isn't even an update post, that would be my definition of abandoment. If you make a product available to the mass and charge for it, there is a certain expectation and etiquette to uphold to give your customers some insight and transparency. A bit of a higher standard than some random posting the first chapter of a fanfic and then leaving it.