Nothing makes me feel quite as incompetent at gardening as when I'm able to kill the plants everyone else says should be foolproof ><
The _ONLY_ thing I can think of after watching your video is that the house gets cold at night, since we only keep the bedroom fully heated, so my current attempt is on my cactus shelf which I keep warmer.
(The link is appreciated regardless, if I ever got one to "stick" I'd love to propagate it)
Unfortunately our house both gets _very little_ light and is often quite cold so that already precludes a lot of options. Some day I'd love to live somewhere that allows the "room full of giant bushy plants indoors" setup.
- If you're fertilizing them, maybe stop doing that. Fertilizer is good when done right, but it's easy to overdo it and burn your plants. Pothos can survive for years in the same potting soil, so stick to plain water and see how they do.
- Give them a small cup of water twice a week. A total of 250mL per week is probably good.
- Put them anywhere near a window, but maybe not in direct sunlight.
- Keep the temperature around 20-25°C (room temperature).
That's basically all I do. The only time I've managed to harm them is from using too much fertilizer.
This happens typically by a fungus attack when the plant roots are left in stagnant water that gets too cold at night. The fungus kills the plant from below.
At this state your best try would be to discard the old plant and use the green part as a cutting. Unroot the plant, use a sharp knife to remove slices of black and rotten tissue (Work from below towards the upper part). With luck you will find green and healthy tissue eventually.
Now clean this upper part and cut all leaves by half (to reduce evaporation in a rootless plant), if the stem is wrinkled put it in clean warm water for an hour. If available, put some cinnamon powder over the wounded area, let dry for a few hours and then repot in a new recipient with some moisture. You can use a half plastic water bottle with holes at the bottom, (thus you can take a look for new roots).
The plant will probably not do too much until spring, but this is normal. To be successful you will need a warm area (71-75Fº), some light, and good soil.
About the soil. The cheap stuff in your photo is probably the main reason for your problems to keep plants alive. You are using a poor quality mix of compost and polystyrene, too dry and low in nutrients. Don't recycle it!. Just pick some standard soil from a garden, an orchard or (even better) a forest. Normal earthworm soil will be great.
Is still possible to save it. Dracaenas root easily from cuttings (the inferior leaves will be sacrified in the process by the plant but new leaves will regrow soon after the new roots are ready). Good luck