Who was the person standing at the gravestone, drinking, and talking to his “Brother”. A father’s brother may even be called an “Uncle”…
Probably Lorath in D3, just aged.
If you look closely in the shot of the shack, you can see what looks very much like Lorath’s polearm in D3, so it could indeed be Lorath or any other Horadrim since I think they all carried the same weapon in the RoS cinematic.