That is a tragic story, indeed! I have done this very procedure many times, so have courage. You can go about this two primary ways: the first is simply to repot the entire tree; the second is to cut off the healthy top and root it, and also repot and hope the trunk and rootmass survive. I think it is imperative that you use a free-draining potting mix. I use bark, perlite, lava rock, and just a little potting mix as a binder/moisture retentive ingredient. And when I say "a little potting mix," I mean less than 10% of the overall mix. If you can't mix your own, I recommend a fine-grade Orchid Mix, to which you will probably add some coarse Perlite. Repot keeping the roots moist at all times, thoroughly water and saturate the new mix when done, and place the tree in outdoor shade if available - no direct sun. Keep the mix uniformly moist with light waterings for at least a week after repotting. You can either repot the tree first, and the cut the top off....or you can cut the top off and repot the tree all at once. It's a bit of a gamble, as I don't know the vitality of the tree, but I have confidence from repeated experience that the top will root (if it is healthy as you describe). I place the cut top in a vase/jar of water, and I wait for white root primordia to appear. As soon as they appear, I transfer the cutting into a container of the same moist, free-draining mix, and I keep it moist while the cutting continues to root. I use #1 nursery containers.

My guess would also be a nutritional deficiency, and I agree with the repot, though it would be better if you waited to repot until June, when the plant should make the fastest recovery. Keep in mind, a repot is much more extensive than simply potting up. Between now and then, I would: * Flush the soil very thoroughly the next time the plant needs water and fertilize with a soluble synthetic fertilizer with a 3:1:2 NPK ratio. RATIO is different than %s. 24-8-16, 12-4-8, 9-3-6 are all 3:1:2 ratio fertilizers. I highly recommend Foliage-Pro 9-3-6 because it contains all the nutrients essential to normal growth in a favorable ratio (to each other) which can be very important - especially so if you're using a soil that forces you to water in small sips to avoid root rot or suppressed root function due to soggy soil conditions. * Fertilize regularly with appropriate doses. We can figure that out once we know what you'll be using and figure out how close you can come to watering correctly. For best growth and vitality, make sure that when you repot, it's into a soil that allows you to flush the soil of accumulating salts at will. You'll be at a turning point in your ability to maintain healthy plant material consistently once you understand how much influence excess water retention has in limiting your plants, and how much easier it is to grow things when you can water properly. The ability to water correctly is also a key element in your ability to take and maintain precise control over nutritional supplementation (fertilizing). Questions? Al

I would suggest bringing it outdoors under full sun, and keep the soil well drained. I'm not sure if your stem is rotting, but if you have plenty of live parts, they are pretty easy to root when they get stuck in soil with some type of a rooting gel, but the key is to make sure the soil is well draining and never gets damp. Here's a link to when I propagated mine. I got 8 out of 14 of them to root as it seems like the smaller green parts don't make very good divisions due to their vulnerability to rotting off. I simply plant them, and leave them alone for the most part. It has been just over a month and they are starting to form buds to generate new leaves, but rooting usually takes another month or so. I split up my pachira aquaticas every year. Here is a link that might be useful: Dividing up pachira aquatica

Thanks. I love this tree and it's super easy to care for.