They do not only do zero humanitarian work but severely hamper that of those who want and can help.
Yesterday I watched in TV returning Spanish rescue specialists that complained that they were forced by the invaders to stop their work at 5pm and severely restricted their activities on "security grounds", when they say that they never felt any threat at all.
Some propaganda images of the marines distributing aid have been spread by the media but RNE journalist Fran Sevilla absolutely denies that they are doing anything at all, not even patrolling much. They have taken indeed control of of the Port-au-Prince airport and give absolute priority to their own deployment and the evacuation of US nationals, in practice blockading the the aid distribution.
France and Brazil have joined the chore of complaints by many Latin American countries against the ugly reality of US unilateral intervention. Bolivian President Evo Morales is even organizing a UN meeting to demand the retreat of US troops on light of their harmful activity.
Physicians without Borders and Intermon OXFAM have complained that their aid is stuck at Santo Domingo unable to reach Port-au-Prince because the marines don't give them authorization. .
The maybe feeble but anyhow real, aid organizatiod by the Haitian government, that had moved its headquarters to a police station near the airport, has been totally overruled without legal authority by the disproportionate, meaningless and useless US military invasion, which seems more designed to promote obscure imperialist interests than to help in any meaningful way.