It is controlling and your mother's opinion of how you should arrange your house, you should try to chuckle at and cheerfully let her know it isn't how you see things. My stepmother did that, when I moved to my apartment she did not like where I put my bed in my studio apartment because the head "would be facing down the hill" (outside, the street was a hill! Who cares what's happening outside when arranging one's furniture inside?) and I liked my furniture off the rug but she insisted they had to be part on and part off or the rug was like an "island". I did recognize my stepmother had been dealing with moving furniture a good 20 years or more longer than I had so I admit the second "island" thing makes sense but I did have to seriously laugh at worrying about my head facing downhill?

If your sister gave you the drawers, call her and short circuit the sister-to-mom-to-you thing going on. Tell her you heard she was interested in the drawers but you're sorry, you're using the drawers and can't spare them now. It does not sound like sharing your plans with your mother is very helpful, she wants to butt in (not her business about the lodger and what furniture you would like in what room; besides, possession is 9/10ths of the law :-) I'd tell her you'd really like X and Y furniture she wants to give you but you you and your sister will be making your own plans together for after she leaves, you aren't interested in thinking about it right now and it's sweet she's thinking about you but buy, isn't she stressed enough having to move herself? (In other words, "Don't worry about me, I can take care of myself").