My sister had fallen about 2 months ago. All the injuries have healed, except her knee. It seems to be like when I tore my cartilage. Before going to a specialist she'd like to know what she can do at home first. Of course I think she should have it elevated and off it as much as possible. Should she wrap it and ice or heat.

Ice is for swelling when an injury is new. Heat (moist) is for strain, soreness, aches, and so on. Use a damp washcloth on a heating pad. Take warm baths. And always, or at least as much as possible, move the knee around gently, and walk. Staying off it is not as important, as long as the movement is unstrained and she isn't carrying loads.
If she sits at a computer, her chair MUST be low enough that her feet can be flat on the floor and her thighs aren't pressed against the chair. She shouldn't tuck her feet under the chair, and she should move her feet around, and she should get up and walk at least every 20 minutes.
If she hears significant creaking at the knee and/or feels a soft raised spot (fluid) she might as well go now as later. Loss of synovial fluid or torn anything needs attention.