Is it permissible to give Zakah (obligatory charity) to one`s poor sister, or brother?
                                It is permissible for one to give the Zakah to his poor sister, or brother if providing for them isn`t due on him, and the sister doesn`t receive sufficient provision from whomever that is due on. And Allah Knows Best.
                             
                        
                            
                                
                                In our region in southern Oman, specifically in the city of Taqah, there is a mosque that they say was built hundreds of years ago. This mosque is surrounded by graves, meaning it is in the middle and the graves are around it. People in our area differ, with some considering it permissible and others considering it forbidden to pray there. Moreover, my grandmother saw in a dream that she entered this mosque..."
 
                                Praying in this mosque is valid and and there is reprehensibility in its location so long as no grave exist within it. Besides, Sharia rulings aren't derived out of dreams. And Allah Knows Best. 
                             
                        
                            
                                
                                How to pay Zakah (obligatory charity) due on articles of merchandise?
                                Articles of merchandise are estimated by their whole sale market price at the end of each lunar year, and (2.5%) of their value is paid as Zakah whether it (value) went up, or down compared to actual purchasing price, and whether the increase (profit) was in the article itself such as an increase in the animal`s weight, or in the prices themselves. And Allah Knows Best.
                             
                        
                            
                                
                                Is everyone obligated to follow the fatwas of his country, and if we adopt the fatwas of scholars of other countries, is it considered a sin?
                                All perfect praise be to Allah, The Lord of The Wolrds and may His Peace and Blessings be upon our Prophet Muhammad and upon all of his family and companions.
It is permissible for the person who isn't specialized in Sharia sciences to apply the opinions of renowned scholars whom he trusts ,whether they be from his own country or not ,but if the scholars have different opnions regarding a certain issue/matter, then he must consult someone who is more knowledgeable than himself .It is preferable that you (the questioner) specify the case of your interest ,so that we could give you a more specific answer since some scholars deliver fatwas based on illogical/atypical opinions which should not be applied no matter what .And Allah The Exalted Knows Best.