The major problem being that he allegedly hid his income from the IRS including at least one million dollars in gifts from Chinese officials. This isn't speculation, they know he received a huge diamond from them and didn't tell anyone. In following the money trail, they found that he did use these other sources of income to pay off his obligations and enhance his lifestyle. Not good.
All the bad things that Al Capone did, and it was the IRS who tripped him up. Hunter has done so many bad things and he'll probably get away with some, but the IRS can slime you like no one else can. I'm looking forward to seeing it.