My goodness NO.....You have ZERO liability! This person considers you a friend who trusts you enough to vouch for their character, simple as that. It does not matter where you live. You are WAY overthinking this!
I got an email asking me to be a "reference" for someone I know that is looking to get a firearms permit. It's worded like, "xxx is being investigated to determine his/her suitability for the issuance of N.J. Firearms Purchaser Identification Card and/or Permit to Purchase a Handgun. This individual has identified you as the background reference in their application. Your feedback is essential for further processing of this application." And then has a follow up link for me to fill out some questions.
Am I liable for what this person does with his/her firearm after I fill this out? For example, I'm worried that if I am a reference and years later this person is convicted of a crime involving a firearm I will somehow be implicated because I was his "reference". Has this happened or is this something I shouldn't worry about? I live in monmouth county if it makes any difference.