Dad does asset sale to son: successor plan?

[AlbanyConsultant]

Dad owns 100% of Dad's company.  He did a full asset sale to Son (his son, age 21+), who has created a new company for this.  The employees are terminating with Dad's Company and are being hired by Son's Company.

Dad is terminating his plan effective 1/1/24.  Son is looking to start up a plan in early 2025.  Are we (they) going to run into the successor plan rules because of the relationship between Dad and Son?  There was no direct ownership by Son in Dad's Company, and there is no direct ownership by Dad in Son's company.

Thanks.