Can you tell me what you suggest if someone is using methadone, can they get high of other drugs?

Not sure what you: Are really asking. People on Methadone can and do abuse other drugs, including opiates, but they need much higher doses to get "high, " and this tends to reduce their desire to do so. However, they can still get effects from alcohol, sedatives, stimulants etc. This is why programs include counseling to change the way you live, and treatment for other underlying psychiatric problems, esp. Trauma.