Correct usage in relative clause

I need to find the man whose son you said (((he))) tried to find a job .

Should I use “he” after “you said” ? Or it can be understood that “ the one you talked about is son of the man ?

Your example is correct without 'he'. It is incorrect with 'he'.

In this case, 'son' is the subject of the clause so if you add another subject, 'he', it is redundant. We know the son is the son of the man because of the possessive, 'whose'.

His son tried to find a job.
He is the man whose son tried to find a job.
You said his son tried to find a job.
He is the man whose son you said tried to find a job.