I've tried growing these things in my house before and they are indeed finicky. They need substantial humidity to thrive--have you done anything to supplement humidity where it's growing?

I've also never understood that ice cube thing; I've heard about it being done with orchids and didn't get it. We're trying to provide conditions as close to the plant's native habitat as possible to get it to thrive, and I'm sure these plants don't receive an incredibly slow trickle of icy water in their tropical homes. Usually watering with lukewarm water is recommended because some plants are sensitive to cold water. As long as you're watering it thoroughly enough that water comes out the drainage holes and the soil is saturated throughout, you shouldn't need to also do the ice cube thing :)

Maidenhair Ferns (Adiantum ssp) are usually sold in a very light mix which drains fast but also dries out fast. You have to be careful that you give the plant sufficient water and never let it dry out. If those photos are the "after" photos then I'd say your plant is still okay. But they will retain their green colour if they do dry out and die, it's a bit of a different shade of green. New crosiers or new leaflets will look wilted. I've never used ice cubes on plants, it seems counter intuitive to me.

It will probably have to go in a terrarium type thing to do well long-term indoors. Mine died indoors but I have one doing well outside in the shade this summer by my east facing front porch.

When in the house I water my maidenhair ferns every other day. Water until drainage dish has water in it. Let stand for a couple hours and then pour it out. I put my ferns in a north window or south window behind sheer curtains. If you have your ferns outside...be prepared for them to look sickly till they get adjusted to being inside.