Some things to consider: If it's on an east windowsill, (it's almost a given) it's not getting enough light, and it might be too cold there for the plant. (Your user info doesn't tell us where you live - you might wish to fix that. It makes it easier for others to help.) Soil temps should be above 60* always. They will tolerate lower soil temps for a while, but they prefer soil temps in the 65-75* range. If you're trying to water once each day, it's very likely that you're over-watering. In most cases I've seen, the bonsai soil sold at bonsai shops & even by bonsai clubs is finer than ideal. The reason is two-fold. They are trying to make a profit, so screening the fines out of the material is both an extra step (time is money) and they would lose a considerable fraction of the products they are using to make the soil (which they had to pay for) if they screened out the inappropriately-sized particles. I didn't say that to disparage the soils, I said it to impress upon you that you need to be very careful about how you water bonsai. Because of the shallow pots, ANY perched water table (PWT) is a large fraction of the soil, and PWTs kill roots. E.g., if you are growing in a pot that is 3" deep, and in a soil that supports a 1 - 1-1/2" PWT. 1/3 to 1/2 of your soil remains saturated after you water. This is decidedly bad for your roots, and may be why your tree is suffering. Water AS NEEDED. Use a sharp dowel & stick it in the soil all the way to the bottom of the pot. Don't water until it comes out clean and dry. After you water, tilt the pot steeply toward a drain hole - it will cause MUCH more water to drain from the soil. Try it. Water, making sure you flush the soil, & wait for the pot to stop draining. Then, tip the pot so a drain hole is down, and watch how much more water exits the pot. Also, use a wick to help with drainage - you can also use the wick as a 'tell', to let you know when it's time to water. You can read more about tips on how to deal with excess water retention by following the embedded link. Have you been flushing the soil regularly? Where do you live? Are you fertilizing - with what - what strength? Al

If not grafted "suckers" are same tree and should be left - especially if they might eventually fill back in where there is dead. Cut the dead and leave the rest, unless tree is grafted. Cutting back a Kousa or other dogwood of this type spoils the shape of the branches.

It's not cheap ==========>>> when planted .. did you unwind circling roots... any additional facts about how it went in the ground might help i have no clue about your reference to your old post ... any chance at a link???? as to cost ... i would not spend more than a replacement tree at half the size ... and i would have never put 15 cups of anything around a tree .. whatever its problem is.. it was not a fertilizer issue ... especially if this tree is in the middle of a fertilized lawn .. which by the way .. any history of weed or crap grass killer on the lawn??? regardless.. hollytone is so mild i doubt it hurt the situation ... the bottom line.. in my warped world.. it isnt worth spending hundreds of dollars on repairs for a $50 tree ... ken

I see this effect on my 'Bloodgood's when they get Verticillium wilt. A slow gradual die-back from the tip to the trunk. When you cut the dead branches, did you see areas of jet black or jet black partial circular rings? I hope you sterilized the blades after each cut. If you have V wilt, you can extend the life of the JM using a product I buy from Mountain Maples in California called Phyton 27. If you have V wilt in will remain in the soil almost forever and you'll need replant a V wilt resistant plant.