If he went undrafted, he'd be a priority free agent signing for me. Raw but that size, strength, and speed is not normal in human beings. Biggest obstacle in sports transfer to football is the toughness, physicality issue, BUT this kid is a rugby player so that shouldn't be an issue.
I don't know what he is, but he's only 20, 6'8" and 345 lbs. and has movement skills. Could be an offensive tackle, could be an almost unguardable TE (probably not with a 5.12 40 time), or a defensive lineman that will black out passing lanes.
The last kid that intrigued me like this was a 6''9" wide receiver at Army. He's now the starting left tackle for the Steelers.