Palm wood is always very heavy and dense. I've never seen anybody selling stabilized palm, but there is a first for everything. The structure is exactly like a handfull of pickup sticks glued together with a mixture of yellow glue and sawdust. The black straws are very hard and dense, and tend to splinter, and the matrix tends to be dry and much softer. Sometimes a black straw will want to break loose from the matrix rather than cutting and that makes a mess. If you catch it early enough, ca it back in place and keep going. For drilling, if the blank is much larger than the tube, you should be ok, just go slow, clear the bit constantly, and if you are doing a two piece pen, cut the halves to length plus a fudge factor before drilling, rather than trying to do it in one fell swoop. If the blank is smaller and you are using a larger kit, you might consider wrapping the blank in a couple layers of gauze and soaking with med ca, then wrap in a piece of paper to pull everything nice and tight, let dry, trim paper and then drill.
The gauze and ca is a trick I got from Eagle, the paper is from when I got tired of it having air pockets on the surface of the blank. It works well for any delicate blank, or segmented ones as well.