None of you old geezers have heard someone say "That ass tho!" or maybe "Dat ass doe" when talking about some hot chick's ass? It's just a word thrown on the end to show extra excitement over a particular subject. It's like taking the front half of the statement off and just leaving the end...so instead of saying "Yea, she's hot but I'm lookin at that ass tho" they just say "That ass tho".
So Caleb most likely uses it like, "I like the recruiting process a lot but this is dope tho"...or something along those lines. He just left off everything before "this is dope tho". That's just a possible example.
So basically, this is a good thing and nothing negative should be taken from it based on how younger kids speak in this day and age. It's not ebonics or anything either. Caled just likes the message in the graphic...same as us.