Okay, let's recap... Your plant's not happy, which means something needs to be changed.

What you describe sounds like a problem with water uptake. That suggests the plant isn't in the best media. I would first and foremost unpot it and examine the roots. They will give you the info you need to correct the care of this plant.

You know how you been watering. If you believe you're doing the right thing, then dry crispy roots say you potting mix and pot are too open. If they're rotted to any degree, then things are too closed and you need to get more air in there.

It's time to unpot this fellow and see what the roots say... Let us know what you find - we're here to help!

Julie