not interested

I have a problem with my 14 year old son and school. He was held back in first grade because of how his birthday fell and he did not pass six grade because of failing grade's. He was diagnosed as ADH at age 8 after his teacher suggested that he be tested. For two years we tried different medications with no change of school improvement. When I asked the doctor on how much of his actions were ADH or just a boy at his age he didn't know, After that i took him off medicine and tried health product Focus. nothing has seemed   to work . He has never been a over hyper child and shows none of the symptom's connected with ADH that I can tell. Complaints from his teachers have been the same for the last two years, If he is not interested in the topic then he will not apply himself with doing any of the work. He is very smart at home and talks about different subjects that he has learned  or likes but this seems to vary often. He plays guitar and only needs to hear a song a couple of times before he has figured it out on his own so I know he is capable of doing school work. I have tried grounding him, taking away privileges ect nothing seems to work. I feel that I am beginning to sound like a broken record. He seems to be two different children between here and school. I am a stay at home mom and try to stay on top of who he is with and where he is. I  call and talk to his teachers every two weeks to find out what he is doing and what he has not done. I don't know what else to do if anyone has an ideal please let me know.

[SeriousSam]

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