Prof not responding and it is almost the deadline

[dldfj]

So one of my recommender agreed to write me a letter some times ago and asked me for some supporting materials. But since then I have received no response from him (I emailed him like once or twice). My advisor told me that he was probably waiting for the links sent by the schools' application system so I just sent them out. Now the earliest application deadlines are approaching. I sent him a reminder recently and still no response, and the application portals say that he has not started yet as of today. What should I do? 

[Crucial BBQ]

For better or worse, it is out of your hands.  Not sure what else to say other than if a professor agrees to write an LOR on your behalf they truly have the intention to do so.  I wouldn't be surprised if it gets submitted at the last minute.  Unless the deadline was December 1, I would send a final reminder a day or two before the deadline and then hope for the best.