Hi, The faucet in the kitchen is loose due to leaking. The wood under the countertop was damaged due to leaking water. This makes it very soft and difficult to tighten the nuts. From the picture, there is very little space for me to put the basin wrench into the "horseshoe" to tighten the nuts as you can see in the picture. In the picture, the yellow plastic line is the water coming to the faucet, the other two pipes are cold and hot water pipe. How should I do it? thanks! Yiqun
That type of faucet typically comes with a special deep socket tool to make fastening easy. Without that tool (and they are not "universal"; each faucet make/model may have different size/style) you are left to making some other tool work as best as you can (long handled plier, basin wrench, crowfoot wrench, adjustable wrench, etc.)
I would never attempt to tighten that up with those hoses in the way, remove them first to facilitate access.
You say that the mounting surface is "very soft and difficult to tighten the nuts". I am afraid that will be a problem for you. You really should remove the entire faucet and repair/reinforce the damaged sink.