If he was going through a divorce, his ex could have accused him of something to get custody of the kids. 

@Emily RefiThe two common choices for investing retirement funds into real estate are the self-directed IRA and the Solo 401k.The Solo 401k requires self-employment activity, but will allow you to take participant loans while the IRA does not.A few other Solo 401k benefits: Compared to an IRA, Solo 401k contributions limits are roughly ten times higher.There is no custodial requirement for the 401k.You don't need the additional expense and administration of an LLC to have checkbook control.There is a built in-Roth component whereas IRAs are either traditional or Roth, not both.A spouse can also participate in the same Solo 401k plan.The Solo 401k has additional tax benefits over an IRA when investing into real estate using leverage.The penalties for prohibited transactions are less severe, though it's best not to utilize this benefit :)With either structure, it's generally recommended that you do not commingle retirement and non-retirement assets.

As a single dad with sole custody, the kids have always tagged along in some way - sometimes looking over my shoulder at the computer, sometimes riding along to look at property.

There are two potential options: 1) You can have a custodial account with one of the self-directed custodians.