Coconut palm is very brittle.
I've had good luck using 3-flute spiral solid carbide bits [www.cuttingtoolsource.com]
I run rpms at 18-22,000 and feed rate 40-50
When possible avoid square corner cuts that go across the grain, if possible extend the cuts past the corner
This works with red oak too
You can do this by making cross cuts first [use layers so you can create separate tool paths]
If 3d carving try to follow the grain just like you would on a planer, jointer, or hand plane [avoid running the cutter cutting into the end of the grain]
If your wood is really dry you may need to first soak with wood hardener, peg, penetrating sealer, or etc.
I sometimes dilute wood hardener so it dries slower and penetrates deeper
Good Luck, the character of the wood is worth the effort
You will get old if you live long enough!