Funny,I have just applied this morning for a visit visa for my mother too.
For people born before 1945 you have to get the approval of an officer,just a formality.
For the multiple entry,I ask about it and they told me that once she'll be here,I will have to apply for a re-entry visa,as they are not processing multiple-entry visas for short stays (I applied for a 1-month visa only).
Hope it will help.