my question today~ i need nice ppl 's help!

look at the this sentence:

he's a single guy that /who doesn't have a job.

i think both that and who are right in this case,  but i need to know the difference to help me understand english better.  thank u! 

that :we use it to define things :

for Exp; I wear the coat that my father gave me

we can also use which  to define things

who : we use it for person or people

for Exp;i saw the man who doesn't have a job.

so in your sentence we dont have choices to use that or who ,but we have to use who because we define a person