I'd like to help you with this: "he transferred that personal business to s corp which is also under his name"

Let's call this what it is, not how you described it.

He formed a Corporation, submitted the election to be an S Corp, then contributed the resources from his Sole Proprietorship business to be Corporate (assets, liabilities, ability and rights to be in business).

I really like web articles that help explain, for instance, the complexity of 351 is here:

https://blog.vcexperts.com/2015/03/16/what-is-a-section-351a-tax-free-exchange/

For example: "The corporation‘s basis in the property it receives in an exchange for its stock is the same basis you had in the property when transferred (in other words, the corporation takes your basis)."

But Depreciation does not transfer into the corporation. It has the Value of the transfers In, and depreciation starts from there.

He also would file for the FEIN and be an Employer, and now he is an employee-shareholder.

There is no Owner.

There are no longer Draws.

You might want to get some mentoring on this.