How to recover all my deleted photos from iphone?

So my grandfather passed away and i had a very cute video of him but thne i deleted it but after his death i want that video so much how can i recover my photos from iphone 4.

Sorry to tell you, but you can't recover it. I'm very sorry for the loss of your grandfather

Did you ever backup your videos and pictures to either iTunes or iCloud BEFORE you deleted them? If so, you may be able to restore them from a backup or the cloud, if not and your have been using your phone since you deleted the video (over a day even, but I suspect you deleted the video some time ago), it may be impossible to recover it.

For the future, also backup and offload your important pictures and videos to as many online and home computer/external drives options as possible. Because those important once of a kind videos, pictures, text, emails and voice mails, are just one toilet, sidewalk tumble or sticky fingers thief, away from being gone forever.

DropBox, OneDrive, Google Drive, BOX, etc are all great options to get things off your phones or at the very least, stored in more than one place.