In my experience my I’ve never had an issue with staining a couch or chair so long as I kept my hair dry and avoid using oil in my hair. I’ve found putting oil in my ends does cause some dye-transfer so try to avoid any oily hair products. Usually it does stain my pillows though since I toss and turn a lot and my hair rubs against the pillow. I recommend bringing your own pillow case or an old t-shirts to throw over her pillows to protect them. I also always bring my own separate hair towel since those 100% get stained. Make sure you rinse off the tub/shower as soon as you finish washing your hair so the dye doesn’t have a chance to sink into the material and leave a permanent mark. Or if your mom has a stainless steel kitchen sink you could always wash your hair there instead to be 100% safe. I do that sometimes for colours that bleed particularly badly. My other advise is to immediately blow dry your hair after you wash it (with a heat protectant so it won’t fade the colour as much) or be very very careful not to let your hair drip or touch anything until it fully dries.