I used to teach a girl with Aspergers. The biggest thing I noticed with her is she had a very hard time communicating what was going through her mind and that would lead to outbursts.
She became very attached to me and thrived off a set routine. What I ended up doing with her was sit down and make a "list". It would almost be a check list for her. It was broken down to the very basics and we would set weekly goals. An idea of the checklist
-Find coach and say hello
-Check the board for assigned horse
-Get brushes and tack set up where horse will be cross tied
-Get horse from stall/padock and crosstie
-Brush horse starting with curry comb, then hard brush, soft brush and pick out hooves
-Put brushes back in kit
-Start tacking up boots on horse, saddle pad, saddle
-Check with coach to find out when to bridle
The list would go like this. She loved having her check list. We had another one for when she was on and starting to ride. It would start with warming herself and her horse up. Arm circles, toe touching, walk halt transitions etc
It seems really silly but she really thrived off having this routine and her goals. The goals would be so simple and basic. One week it was "go entire week without being told to check diagonal" or "work on two point" just little things.
Now my student was only 15. So you might need something a little more advanced then this but I have done similar things with other students that had LD's.
Good luck and if you ever need advice or have a question feel free to pm me. I tend to get handed all the students with LDs for some reason lol and I actually really enjoy it. Its great having these small goals and seeing how excited they get when they reach their goal. One kid is so excited that she's started learning stride control. Another one of my kids just about peed herself from being so happy and excited she mastered a half halt. I just love it