Moist but not constant wet, is the "soil" dirt or more like gravel? If it's dirt and you water 4 times a week it might be too much, tell me there aren't rocks glued on top, Please, if so remove them so you can properly check the soil for water needs. A finger, the tooth pick/ chopstick test are good ways to see how much moisture is in the soil after a while of doing the checks you develope a feel for when you need to water. Some time you can judge by the weight of the tree and pot, but you first have to know the differance between need water, and doesn't need to be watered. Overwatering kills more than underwatering.
All trees big or small need food, but try soonami's suggestion about getting it outside, and hope you get some new growth, then you can start some fertilizing, but it doesn't sound good.
Don't get discouraged if it is croaked though, most of us have learned the same way, and are for the most part better for it, if you cosider being a Bonsai nut better
, I do.
Good Luck
Bill