Hello,

thank you for contacting Ask Extension. Looking at your plant, I would say the first thing is that your pot is too large.  If you pot is too big, the soil stays wet longer and does not drain well, leaving the tree in a wet mixture too long. Money trees like to have their roots a bit tight and they also like a very well draining soil mix. It should be planted in a high peat moss mix that drains well. These plants like to stay moist, but not wet. 

The humidifier will help, but also a tray with rocks in it and water will also provide the needed humidity. 

Now to pruning. You can prune down the length. I found a good resource that will help you in pruning the limbs down. This will also help it to develop a thicker, stronger base. Do not prune more than 1/2 of each limb. You will want to cut down to a node, which is where a leaf has previously come out. I included two pictures of an area that would work to prune back. I would prune it back to those this year, then next year, prune back a bit more. It will probably take about 2-3 years to get the tree looking a bit better.

Good luck, and if we can be of further help, please let us know.

https://www.thespruce.com/how-to-prune-a-money-tree-8690475