Yes, you can be charged with robbery and homicide during a drug transaction; it all depends on the facts. <a href="http://www.legalphilly.com/criminal/murder.php">Homicide</a> is a serious offense I would suggest hiring the right criminal defense attorney to help your nephew out.
In order to be charged for a DUI in Pennsylvania you need to be in physical control of the car at the time you had alcohol in your system. Based on your facts I don't think that is the case. I would suggest hiring a criminal defense attorney to represent you in your DUI matter.
Michael Kotik | 267-265-4553 | www.legalphilly.com
Without knowing more of the facts, the only thing I see here is that you had another person with you. If that person would be willing to testify to your set of facts your might have a good case at trial. There are other factors to consider; like your prior record, your character, etc...
If you are a first time offender (DUI), ARD is also an option. ARD/DUI is a probationary program for first time DUI offenders. Upon successful completion of the probation period, the criminal charges of DUI...
First you need to hire a criminal defense attorney one with complete knowledge of violent crime cases.
Second you might have to go to trial on this to prove your story however I would avoid sharing so much information about your case on this site