How can poor concentration and nail biting habit be cured in a child?

Hello doctor,

This query is about a healthy, happy boy who has poor concentration and cannot stop biting his nails. My 11-year-old son has had a nail-biting habit on and off since his toddler years. We recently moved and started school (were homeschooled before). He has always been easily distracted when doing written sit-down work. He enjoys his new school and is making friends, he can read and listens and recalls story details, good in math. Not hyperactive, just spaces out, daydreaming. Other seemingly unrelated issues: Occasional headaches, outdoor allergies with sinus infections yearly (better since the move). We are a vegetarian family but eat eggs and dairy. He is a very social person, likes building and creating things, and enjoys music and dancing.

Hi doctor,

Thank you for your reply.

To answer more details: He is easy-going in nature, does have sweet tooth, but enjoys other foods too. He can take a long time to fall asleep, but is generally an early riser with good energy. Only constipated when traveling. Not likely to have a tantrum, but can be strong willed and argumentative. He calms down quickly and then able to accept alternatives. He tries to get through his routines quickly, and not giving great care.

He can get angry, argumentative when we tell him for example, to brush his teeth again more carefully. I am not sure on details of his headaches. They mostly happen when he is overtired. He is generally willing to try new things with little complaint.

Thank you doctor,

So Sulphur only one dose and no more or once a day? And then Skatole three times in a day, for just one day? Or for how long?