My fiance's parents and her sister (shes 13) want to fly to the USA and attend our wedding! They are both around 50 and have high jobs in Russia, and there daughter is only 13 (mariyas sister) What are there chancing of ALL OF THEM getting a visa to come out to the wedding? Can I do anything to help them get it?
thanks in advance everyone

By filling out the application and having your parents write a letter inviting them. You will need to help them with the interview: how to prove that they have significant enough ties to Russia that they won't try to overstay/emigrate.

For instance, when the officer asks why they want to go the us, you could tell them that they should say something like, "to help with wedding preparations and attend the wedding of our firstborn daughter" or something like that, making sure to emphasize that they only wish to go to wedding and then return to Russia. There are people who had success in this area with this particular situation.

With my experiance,including working visas and tourist visas...Makes ure they never lie on interview..more honest they are,more chances to get it...
I want my family to visit too,but i am waiting for elections,maybe it will make process a bit easier...
In our case we got married in a court to fit 90 days...but ceremony and honeymoon we doing almost a year later,to prepare better and make it as nice as possible.good luck!