So he's bought himself a weights bench and set it up in the bathroom in front of the door because I presume it can't fit anywhere else. Yep LTB.
That would be the door through which his disabled son accesses the bathroom. If it can't fit anywhere else then he shouldn't have set the stupid thing up at all.
I must admit, OP, you're being more tolerant about this than I would be. I would be telling him either it goes tonight or you do.