Whatever two people want to do should be no one else’s business. I don’t believe the state should be in the business of regulating “lifestyles.” Finally, a partner should have the same legal rights and benefits as a spouse. Therefore, yes, I am for same sex marriage. Speaking entirely for myself, I really don’t understand why it is still “prohibited.”
As for your friend’s family, I detect a hint that all is not as it should be, I hope they find it in their hearts to accept her and her partner just as they are.
One day none of this will be an issue anymore.