50a overhead to garage sub-panel ???'s

[MstrCarpenter]

My nephew has wired up circuits to his garage sub-panel. Now he needs to get power there without trenching due to trees. I'm familiar with main service drops from the pole to the main breaker/panel as well as temp services for job sites but have always gone underground to sheds and garages. I have a spool of "direct bury" that would satisfy the current requirements but I'm not sure if it could also be rated for overhead; I have many other conductors/cables that he's welcome to if it'll pass code. Also not sure if he needs a grounding conductor all the way back to the main panel (vs. a separate grounding rod at the garage). 

Next is the connection(s) at the mast/structure. Typically the neutral is used for securing then all the conductors are spliced with a drip loop at the weatherhead. If he needs a ground, can I assume it's o.k. to use it for securing purposes? 

So what are the wire designations required or allowed (ie. SER, SEU, THHN, THHW) for these three parts of the run?
Main panel, out and up house to Weatherhead:
Weatherhead to Weatherhead; (This is overhead, so how high and what designations are allowed?)
Weatherhead to sub-panel:

Thanks

[srv52761]

Have never run overhead, but it should be a simple look up in the NEC handbook.
Wrt running ground to the main or separate ground rods… yes, and probably.

Sub panels have needed a 4-wire feed for many cycles of the NEC.

If it is in a separate structure it also needs its own redundant equipment grounding conductor.
So you will need a ground wire connected to a grounding system, usually ground rods (2) six feet or more apart.
However, it does not have to be new independent ground rods.  If the garage is reasonably close you can connect to the main’s grounding system.

You must have both, ground from the main AND its own grounding conductor.