I have a Huge Christmas Cactus given to me my my new mother-in-law. When I got it, it was sickly looking with what appears to be cobwebs in it. The leaves are limp but it did flower around Thanksgiving. It is an old plant. What should I do with it to bring it back to health? If this plant dies, I'll never hear the end of it.

Please help.

Patsy

Look closely at the webbing on the cactus, it could be from spidermites, or it could be just from small regular spider that took up resident and maybe still there. You can use a soapy water solution from a spray bottle. For mites, it might take a few good sprays once a week for a few weeks.If you have mites, keep away from other plants that could get infested.
Put the cactus by a window that does not get direct hot sun, or off to the side of a sunny window. Let the soil dry out before watering, then, water enough so it comes out the drainage hole, spill the excess out so the plant is not sitting in water.
Don't fertilizer until spring and only if it's looking healthier and putting out new leaves. (half the recommended strength)
It wouldn't hurt to take a few cutting, 6"-7" Y shaped cuttings, root them in either some water, or well well draining soil in a small pot or pots, but don't keep them wet.

Christmas, Thanksgiving and Easter,they all get pretty much the same care, the only difference is they flower at different times.
jungle cactus care