Re: 'alexander The Great'
It looks like you are confusing things here:
"Alexander now ordered Hephaestion to proceed to Persia with the elephants, the baggage-train, and the greater part of the army. His instructions were to take the coastal route, because it was now winter and he would find in the coastal regions of Persia both warm weather and an abundance of supplies." (Arrian, VI, 29).
Yes, Alexander ordered Hephaestion to lead an army section, however that was in December 325, and after the march through the Gedrosian desert (the (in)famous partition into three parts of the army took place in Summer 325: Krateros led his part through Arachosia, Nearchus sailed along the coast and Alexander, with Hephaestion as we have seen, went through Gedrosia). Hephaestion died in winter 324, in Ecbatana, and Alexander was in the same city at that time:
"At Ecbatana, Alexander offered sacrifice, as it was his custom to do to celebrate a happy occasion. He also held a festival with literary and athletic contests, and drank deep with his closest friends. About this time Hephaestion fell sick. On the seventh day of his illness it so happened that thee was a big crowd at the stadium to watch the boys' races, which were then taking place. During the races a message was brought to Alexander that Hephaestion's condition was serious; he hurried away, but his friend was dead before he could reach him." (Arrian, VII, 14)
"When he came to Ecbatana in Media, and had despatched his most urgent affairs, he began to divert himself again with spectacles and public entertainments, to carry on which he had a supply of three thousand actors and artists, newly arrived out of Greece. But they were soon interrupted by Hephaestion's falling sick of a fever, in which, being a young man and a soldier, too, he could not confine himself to so exact a diet as was necessary; for whilst his physician, Glaucus, was gone to the theatre, he ate a fowl for his dinner, and drank a large draught of wine, upon which he became very ill, and shortly after died. At this misfortune, Alexander was so beyond. all reason transported that, to express his sorrow, he immediately ordered the manes and tails of all his horses and mules to be cut, and threw down the battlements of the neighbouring cities. The poor physician he crucified, and forbade playing on the flute or any other musical instrument in the camp a great while, till directions came from the oracle of Ammon, and enjoined him to honour Hephaestion, and sacrifice to him as a hero. Then seeking to alleviate his grief in war, he set out, as it were, to a hunt and chase of men, for he fell upon the Cossaeans, and put the whole nation to the sword. This was called a sacrifice to Hephaestion's ghost." (Plutarch, 72)
Diodorus (17.110.8) and Iustinus (12.12.11-12) make mention of it too, but I have those two works hidden in some unmarked binder which I'm just too lazy to look for right now.