It's unclear to me what you mean by a "Lump Sum withdrawal" ?
Do you mean a "lump sum" of 12 monthly payments ($2,000 each), or a "Total Distribution" of his entire Accrued Benefit? If he is NOT terminated, does the plan permit In-Service Withdrawals of his entire Accrued Benefit?
If this is a total distribution, and the plan allows In-Service Withdrawals, the total distribution might be worth around $264,000 (2,000 x 12 x approx 11 [APR] ).
If by "lump sum withdrawal", you just mean 1 annual payment (vs. 12 monthly payments of $2,000) you should be able to pay a $24,000 annual RMD payment before 4/1/2023, if plan document allows annual payments of the RMD's.
P.S. you didn't say whether the $1,000 / $2,000 AB's were monthly benefits or annual benefits, but the discussion implied this was a Monthly Accrued Benefit.
.... Jeff