Wedding cake trees are pretty. I think it would be worth taking both soft and hard cuttings now and seeing what happens. Use a hormone rooting powder if you like it. If it doesn't work, well you've lost nothing, and if it does, you have some free baby trees.
One thing to be wary of is whether it may be diseased and this is why it's dying. If that is so then vegetative cuttings would retain the disease.
Have a careful look at why it's not secure - is it the soil it's in, the site, the wind or that it was originally pot grown and the roots never spread out enough. Then if any of your cuttings take you can prevent a repeat performance with the new generation.