My mom visa is denied please help me

hello first sorry for my english
my mother visa is denied today and they gave us 3 reasons
guarantee that after 3 months she will return
and give bank statement
and telll reason why i applied her 
and its tourist visa  but now i dont know its my first time i just applied i just want to know how can i complete this processs and how can i gave them prooof for threee reasons and  one more question  thats i worried about is after i give them reasons how many days willl be for more visa process it will be same again 2 months or it will be lesss i am so worried because recently my father died and i want to apply visa for my mother thanks if anyone can help me

please aybody ??? reply my questions ???

If you want to invite  family members to visit you, it is advisable that you get a "Prise en charge", which is a document issued by your local city hall whereby you assume the costs of their accommodation, their stay, and their repatriation in case they overstay their tourist visa. To get such a document you need a minimum level of income.

You can send the document to the consulate yourself at the time your family members make or renew their visa application. This does not guarantee that your family members will get the visa but it helps. If they are denied the visa anyway, there is nothing else you can do.