you may not get visa on arrival at the air port. But its easy to get visit/tourist visa for close family members .
You can get the form from www.moi.gov.qa
close family means- able to prove the realtion by passport(name of parents /spouse etc)
fill the form by hand,copy of your passport and visitors passport-submit at emigration office near airport(where we got exit permit stamped before) pay Qr 100 by card only
make sure you take seperate passprt copies for each application