I would encourage you take a few minutes to read about the extent of actual efforts undertaken, starting days before landfall, to manage this disaster.
DoD has in fact taken over responsibility for local management of disaster response. I couldn't find a MSM source but you can Google Translate this [1] - god help me I had to find the link on /r/the_donald.
Which is what the Army, Coast Guard, and Marines -- not to mention all those gold bars in Fort Knox -- are for.
If the current administration wanted to flex every available muscle to help the people of Puerto Rico, it would. But very clearly it doesn't.