Don't do it, I would be wary of any elephant sanctuary and doubly so if it has babies you can feed. That almost certainly means they are not rescuing Elephants but they have a captive breeding program and they are then separating them from there mothers so you can feed them. Very few if any countries in the world these days have sufficient numbers of working domesticated elephants to need any form of rescue/sanctuary program so almost all these places are tourist traps exploiting these majestic creatures to put money in peoples pockets and animal welfare will not be a priority.