2 and 1 year visit visa status

Hi friends..
Can anyone here to guide me, if you know about multiple visit visa. My wife and daughter has 2yr and 1 year multiple visa respectively and their visas are going to expire in June 25th 2020. But now their visas 3 months will be completing in May 6th 2020 and after completing 3 months their 45 or 50 days will be remaining. My query is, can I extend those 45 remaining days like we extend 3 months?
I am very confused now because all flights are postponed due to corona virus please help me for your guidance and valuable comments.

New topic