I just received a case where a U-visa applicant was denied because at the time of application he was an LPR. He is currently in removal proceedings and is inadmissible due to a felony drug conviction. I want to counsel him to abandon his LPR status and re-apply for a U-visa. Will his second U-visa application be considered or will it be denied as his first application was denied?

Someone with felony drug conviction is not qualified, except in some cases that the person is key witness in big case... other than that I don't see any possibility.

It will no be denied because the first one was denied, each case would be judged on its own merits. But as noted, the drug conviction should disqualify them.