IMHO, the cessation of contributions (even if permanent) is not a de facto termination. That is why preapproved plans frequently contain an option to maintain any type of plan as a frozen plan, i.e., the plan that precludes new entrants and further contributions (or accruals). I would agree that the distribution of the last dollar of plan assets is potentially a de facto termination.
A plan that has permanently ceased contributions is often called a "wasting trust" and as such, continues to be an ongoing plan that must continue to be administered and updated as an ongoing plan and continue to make distributions to participants, for example, only upon distributable events as defined by the plan (such as retirement). The permanent cessation of contributions (whether declared by the employer or by the IRS) to a profit sharing plan is a de facto vesting event. The document usually has provisions built in with regard to the vesting.
If the owner wants to keep the money in the plan, then the employer has all the duties and fiduciary obligations of maintaining a qualified plan, and is expected to wear the fiduciary hat whenever appropriate, such as ensuring that all required interim amendments for ongoing plans are timely adopted and that the trust provisions are being carried out in a prudent manner (and the owner or someone needs to be a trustee). Since the withdrawal of all plan assets might constitute a de facto termination, the employer should act with caution before doing so (as a plan termination can accelerate the deadline for required interim amendments). The owner should be getting lots of good advice and making a decision one way or the other as soon as possible.