If your friend was arrested on a drug bust, he injured his OWN reputation. This type of reputational injury would not prevent an arrest record from being accessed. In fact, the media could have picked up the arrest of your friend and written about him in the newspaper or broadcast his arrest on tv. All perfectly legal.
When denials of access to public records are based on privacy grounds or reputational injury grounds, this is generally because the individuals involved are minors, or the records involve the victims of a crime. For legitimate arrests and/or convictions involving adults (or minors over a certain age - which can be minors over 12 or 15, depending on the state), the records are considered public records (with very few exceptions).
The arrest record can have most identifying information intact, although social security numbers or unlisted phone numbers will be redacted, as may be any witness names or addresses, or the names, addresses and phone numbers of any minors involved. The arrest record can include officer notes on the arrest and statements made by witnesses or by those who were arrested.
If you or your friend tried to access records without success, it could be because you did not file a proper written request. It could also be because you went to a police station other than the arresting agency to obtain a copy of the report. You need to request the records from the agency that holds the records, which would mean you would file your request for the records with the arresting agency in New Jersey. You cannot file your request with a police agency in Pennsylvania.
You must be specific in your request about what you want - dates, times, names. You need to help the agency narrow their search for the right document. They are not going to go through all of their arrest records to locate the one you want, nor are they required or expected to.
You must also provide the agency with your telephone number, address, or email address so that the agency can contact you. They are allowed time to do their search. You cannot go into the agency that holds the records and expect to have any records handed over right then - especially records that are two years old.
You do not need an attorney to access public records, nor do you need to tell any agency why you want access to the records.
If you feel you were unreasonably denied access to the public record of the drug arrest in New Jersey, and if you followed the proper steps outlined by the New Jersey arresting agency to obtain the records, you can file an appeal. When a request for public records is denied, the agency provides you with a denial letter, which also includes the process for appealing the denial.
The drug arrest of your friend will probably show up on any background check of him, by the way, unless the records were sealed or expunged (which, if this other friend obtained them, is apparently not the case). When your friend applies for jobs, most application forms will require he note this arrest and/or conviction.