In this aspect Ghede is DEATH. He is the keeper of the cemetery and the primary contact with the dead.
Anyone who would seek contact with the dead must first solicit Ghede/Baron Samedi in the same way that Legba is contacted to cross over to the spirit world. He is the loa of death and resurrection. But he is history too. As keeper of the cemetery he has intimate contact with the dead. He knows what their plans were, what's going on in families, what the connections of things are, and is quite generous with his information. Even when he is clowning or performing his erotic antics, if one can pull him aside and ask him a serious question he will give a serious and reliable answer.
Another of Ghede's great powers is as the protector of children. He does not like to see children die. They need a full life. Thus he is the loa to go to when seeking help for a sick child. He has the power over zombies and decides whether or not people can be changed into animals. Any such black magic Voodoo must seek the help of Baron Samedi/Ghede.
Lastly, since Ghede is the lord of death, he is also the final last resort for healing since he must decide whether to accept the sick person into the dead or allow them to recover.