He mentioned another account with min in it. (Pretty annoying as I always ask all of my clients if they have any foreign accounts, pensions brokerage, etc each year and he always answered no). Driving down further. But it doesn't seem like there is any other accounts/income/etc

He is married. Filing a Joint return. They both have SSN, living in the US, etc. 

Researching further it looks like the actual ownership is in a Long-term Incentive plan (LTIP). Which seems closer to a 401K or Bonus plan then actual ownership in the partnership itself. Continuing to research.