Is this person an employee or independent contractor? Who is that work done for?

What was filed for them in the prior tax year? Has anything changed from that info?

Client is an employee, who received deductions for a home office on 2018 return.  Is this allowed for 2019 return. 

You would likely be familiar with Form 2106.

For 2018 and later, this form can be used for Federal tax returns only by Armed Forces reservists, qualified performing artists, fee-basis state or local government officials, and employees with disabilities who have impairment-related work expenses. Some States do not follow that same rule.