new ways to learn. How to proceed?

Hello everyone ,

My 14 year old has mild autism with learning disabilities. He is being home schooled, And he goes for speech and occupation therapy once in a week . He learnt his capital letter alphabets last year with the help of powerpoint presentations and videos at home, that is by connecting every letter to a clue(hand sign / image) .

sometimes , if he is not getting the letter correct, we give him clue, And then he is able to tell. When we got to know this , we made many presentations teaching him number , colors, animals, birds,.etc. He s learning but it is very slow. It looks like he is stuck., or he is bored of this way .. What we do now is make a presentation with lots of animation , sometimes with sound recording.,and play it everyday,My mom sits with him when he is sitting with this...And stops and explains by making a story . Is there any new way to teach him things , something which involves computers,,I realized he loves computers.
Any simple(very simple) games for him to learn ABC, numbers ?? He loves to use computer, but he doesn't know how to operate. We need to put the presentation or video on and then call him. If he is bored , he just clicks randomly and closes everything.!

Any suggestions would help.
Thank you .