Former Vice President Joe Biden promised on Thursday that his youngest son, Hunter, will join the campaign trail, even as his business dealings in Ukraine take center stage.

Biden, who has refused to discuss his son’s business ties to either Ukraine or China, made the pledge during an interview with the Reno Gazette Journal during a campaign swing through Nevada.

“He’s a fine man. He’s been through hell,” the former vice president said of his son, before expressing he would soon be part of the campaign.

The younger Biden has not appeared alongside his father in public in months. Initially, Hunter Biden was supposed to attend his father’s campaign launch in late-April, but those plans were squashed after Breitbart News reported on a 2016 incident in which a cocaine pipe was found in a car he rented in Arizona. Since then, Hunter Biden has kept a low profile, apart from a June profile in the New Yorker magazine in which he discussed his shadowy business dealings and longstanding drug abuse.

Hunter Biden’s reemergence on the campaign coincides with heightened scrutiny over his role at Burisma Holdings, a Ukrainian oil and natural gas conglomerate, and if it intersected with his father’s political influence. The controversy began when President Donald Trump suggested the Ukrainian government look into Hunter Biden’s business dealings in the country, as there are multiple red flags concerning conflicts of interest.

In particular, the most prominent and perplexing concern is how and why Hunter Biden secured an appointment to Burisma’s board of directors, a position which purportedly paid as much as $83,000 per month, in 2014. As Peter Schweizer, senior contributor at Breitbart News, detailed in his book, Secret Empires: How the American Political Class Hides Corruption and Enriches Family and Friends, Hunter Biden had no prior experience with either the energy industry or Ukraine before being tapped for the position.

The lack of experience, coupled with the fact that Joe Biden at the time had just been made the Obama administration’s point man on Ukraine, immediately raised questions from ethics watchdogs in both the U.S. and Europe. Adding to the ethical cloud surrounding the appointment is that at the time of Hunter Biden’s appointment, the company’s founder, Mykola Zlochevsky, had his assets seized in Great Britain on suspicion of money laundering. Many believe Hunter Biden’s position resulted from an attempt by Zlochevsky to curry favor with western leaders to prevent further scrutiny of his business dealings.

Such an attempt would not be all that out of character for Zlochevsky. The Burisma founder is rumored to be one of eastern Europe’s richest oligarchs and was known for cultivating strong political ties to former Ukrainian President Viktor Yanukovych — a staunch ally of Russian President Vladimir Putin. He is also a former Ukrainian minister of natural resources who is widely believed to have used his office to further Burisma’s oil and gas interests.

It is in the context of Burisma and Zlochevsky’s legal troubles that Joe Biden’s conflicting interests have drawn the most suspicion. The former vice president has particularly drawn concerns over his conduct in demanding the Ukrainian government fire its top prosecutor, Viktor Shokin, in 2016. Biden has officially claimed his demand and the threat to withhold more than one billion in U.S. aid came from then-President Barack Obama, who allegedly had lost faith in Shokin’s ability to root out corruption.

Unofficially, though, it was well known that Shokin was investigating both Burisma and Zlochevsky for wrongdoing and public corruption. It is unclear if the probe extended to Hunter Biden, although Shokin has recently admitted that prior to his firing he was told to back off the matter. Regardless of what exactly occurred, Shokin’s successor closed the investigation into Burisma and Zlochevsky, allowing the oligarch to return to the country after having fled it in 2014.

Since Trump’s suggested the matter be looked into by Ukraine’s newly-elected president, an action that launched an impeachment inquiry by the Democrat controlled House of Representatives, Biden has worked to minimize his role in the proceeding. To that end, the former vice president has claimed neither nor his son acted inappropriately and an impeachment probe will prove as much.

“I’m also confident the American people know me, and they know my son,” the former vice president told the Gazette Journal on Thursday.