I’m not sure what you expected from him but he did “show up” for the briefing with the Governor and representatives from other responding agencies. The search and rescue efforts are still underway so there is little more that he could contribute with his presence.
It’s apparent that there are efforts by some to exploit the disaster for political purposes and damage the President and First Lady. This was expected. Most Americans are likely ignoring the political attacks and applauding the dramatic scenes of Houston residents and first responders working together to help those in desperate need.
As you indicated, we will have to wait and see if Congress follows through with sufficient aid appropriations. Presently, it appears that federal and state officials are providing a coordinated response to support the ongoing search, rescue and recovery operations. That’s what is needed at this time; not political grandstanding and snark.