I have the same problem with my DH. He has a "nest" all around his chair. I put a cabinit, table and small book case next to his chair to help control his "nest". It's all full and she's still using the space around his chair for the things he needs to sort out or decide what to do with.
He drives for the Amish so when he is gone for a few days I get a box and neatly park up most of it. He hates when I do that but seems not enough to do it himself.