When is 401(k) plan considered liquidated with installment sale of a plan asset?

A physician (of course) has owned  a part of a business in his 401(k) account (yes we've been filing 990-Ts.)  Now the partnership has been sold and he is receiving amounts in 3 installments 2023 (already received), 2024, and 2025.  He says the plan is now closed since all cash has been paid out but there is an A/R for the other 2 payments.  He says the other payments will be made to his Rollover IRA per his broker.  I mentioned 5500s for two more years and likely required plan amendments.  He sold his practice and so he wants the plan to go away naturally.

The other option  could be to file a 1099-R for the entire amount including the 2 receivable payments and so to treat the remaining two payments as receivable to the IRA.  can an IRA hold an A/R or note?  If not would the IRS match the plan 1099-R to the IRA rollover 5498?    The other 2 payments might total $80 to $100K.  And so our 1099-R woudl be very different than the 5498 filed by the recipient IRA.

I know I can advise and he as Trustee and Plan Administrator can provide direction.

Comments? Thanks

Tom

Tell him to find an IRA to take the note or whatever it is for the 2 remaining payments and roll it to that IRA.  He may need an IRA custodian that holds non-traditional assets, not your problem.

Tell him to provide an independent valuation for the the value of what was rolled to the IRA.

Report that value on 1099-R.

File final 5000 series return.

Direct him to ERISA counsel.