Permanent Visa to Turkey.. applying from Riyadh? [xpost from Turkey]

Hello guys!
I wanted to ask you guys a question for my friend.. I've posted a similar topic on the Turkey board but I'll ask here as well, it doesn't hurt right?

So.. My friend is a student, He is studying here and is on Grade 12 (just gave 11th grade exam and now the session will start soon).... and he wants to apply for a permanent visa to Turkey.

Not just randomly, but because his older brother lives there and has the nationality, he lives on Gaziantep.

Now I'd like to also include that.. well, his father isn't here anymore.. and so his brother can act as sort of a guardian. Would this be possible? The embassy here on Riyadh (Saudi Arabia) won't let him give a permanent visa, they only offer the temporary one... I don't know why?

Can anyone with.. I don't know, some sources around here convince or talk to these people on behalf of us? or guide us on what to do? we're not sure on what to do nor we know the procedure on what happens and how it happens.. so anyone expert here or something, please? really urgent here.. thanks!