I am working with a 10 year old boy who is autistic. His goals are manageable for me with the exception of one.. he is hitting his younger brothers but obviously I don't see this when I am working with him. He just had a recent eval done. The goal is: "blank will improve pragmatic skills by using appropriate verbal language to resolve conflicts with no yelling 4/5 times etc.. Well as I never see these behaviors I can "talk" to him about this till I am blue in the face. Any ideas? Family doesn't have internet so can't show him anything that might be appropriate on YouTube regarding inappropriate behaviors.  One thing is good though whenever I see him and ask how he has behaved since I last saw him - he will say good/bad and/or that he did hit his brothers. It's normally done when his younger brothers take his stuff etc. I just don't know how to help him in this area. Any advice appreciated. I'm an SLPA..
It doesn't sound like it's necessarily an appropriate goal for you to be addressing, considering the setting, unless he is yelling when he is with you.

If you haven't already, I'd speak with the SLP who wrote the goal and ask what she/he had in mind.
You can make a social story for him that his parents can take home. Ask Mom when he usually hits his brothers and come up with a few social stories she can read to him when it occurs.
Any chance you could bring younger brother into the session and problem solve/address if/when it happens?
Time to break out the visual supports! A contingency board or turn-board might help...

A contingency board is a way of showing two possible outcomes for a situation, based on an individual’s choices. The possible choices and rewards can all be attached to a blank board via Velcro, or a complete board can be constructed in Boardmaker or a similar program. A green bar is used to depict socially appropriate choices the individual could make, and the reward that can be received if the “green” choices are the ones chosen. A red bar is used to indicate the socially inappropriate choices the individual could choose to make, and the resulting consequences.

A turn-board is a way of using photos of people and check marks or stickers to indicate whose turn it is in a game/conversation/to have a certain toy.

I have a whole handout on visual supports that includes these, if you message me an email address I'd be happy to share it with you. You will need access to Boardmaker to make the items.