I still don't understand the problem. If I take a bona fide participant loan, complete with appropriate paperwork, there is an obligation to repay the plan. If someone chooses to make the payments for me (my parents, employer, friends, children, The Halfway House for Wayward TPA,s, whatever) what difference does it make? The plan is whole, and the repayment obligation is satisfied.
Now, the fact that someone is essentially giving me a gift may possibly have other implications for the gift giver, or perhaps under some circumstances there may somehow be taxable income to me - that's another issue, and I have no opinion on that, but I don't see how there is any PLAN problem.