For two years, we have been renting out part of our house to a family who we were introduced to through church. Our family is no longer part of said church, but we are still on friendly terms due to them having no other place to go. Now their son in particular, is nothing short of rebellious. He has been smoking since the age of 11 (according to him), even smoking during exams, and regularly gets drunk with mutual friends despite the fact that he is still underage by law, and has recently been driving under the influence without a driver's license. (He turns 18 in November, which is the legal age for both driving and alcohol consumption in my country). He is not an abrasive person, in fact he is quite tolerant and laid-back, and has shown this personality around me all the time.
A bit of background about me: I am 24, and heavily introverted. I have generally gone through a rough childhood where my parents have sheltered me from most childhood activities, and have been very hard on me when it came to making my own choices, hence my introversion and inability to be firm about a decision. I still live with them so they would most likely severely punish me if they found out the truth about him, as he is very good at keeping it a secret from both of our families.
As a result, I have grown to appreciate solitude a lot more, and don't make friends easily, especially if they're the children of family friends, who are outside my age group. This is why I refer to him as an 'acquaintance'. I have regrettably lied to him before about having 'other commitments', and we do still spend time together when the activity is deemed 'moral' enough by both of our families, (e.g going to the movies).
I have just recently acquired my driver's license, so while I can legitimately get away now, it also opened the door for him to potentially use me as a free taxi service, which I obviously don't want. I also definitely do not want him to coerce me into breaking the law in my family's car. However, I don't want to hurt anyone's feelings when making a decision, so I want to know how to decline his frequent invitations to go with his other friends to break the law by speeding excessively, and driving under the influence, without lying or offending his feelings, and also to let him know where I draw the line about his habits while abiding by the same principles outlined above.