Not sure of the Sire but the Dam is 15H, sire was meant to be a bit bigger. My guess is around 15.1...not sure of his breeding all together as cobs can have all sorts in them! But his markings lean towards a Clydesdale in the lineage.
He will probably be around 15-15.1hh. Horses gain most of their height as 2 & 3yr olds & then it really starts to slow down as they begin to put on muscle instead of height. I think he's got another 2 inches in him ;)