You say "entity".  Is this a LLC or similar legal formation?

Your question indicates you are going from a more than one entity (Partnership) to a one person entity (Sole Proprietor). This would indicate an answer of YES.

The Sole Proprietor may not even need an EIN. 

But if this is one "entity" (such as a LLC), the answer is "no".  A Multi-Member LLC changing to a Single Member LLC does NOT need a new EIN for the LLC.  But for purposes of W-9s/1099s, the person probably would want to get an EIN in their personal name.

Its partnership. Mother and son, but mom has passed away.

Thank  you.

This is from IRS:     Here is link for you to research: 

https://www.irs.gov/businesses/small-businesses-self-employed/do-you-need-a-new-ein

Partnerships

You will be required to obtain a new EIN if any of the following statements are true.

• You incorporate.
• Your partnership is taken over by one of the partners and is operated as a sole proprietorship.
• You end an old partnership and begin a new one.