There are two kind of 'adapters' in this discussion. The first one is the physical connector, which allows the plug to be compatible. This is a must to have, and easy to find, just look for a 'universal adapter' in the store.
The second type is the electrical converter allowing a 220v power from the wall plug to charge a device with a power adapter made for 110v. This is called a step-up/step-down transformers and can usually be found at the nearest electrical/appliances shop.
However, the good thing is that most of the AC adapters for small/handheld electronic devices since the late 90s (cellphones/tablets/laptops,etc) are built for 'dual voltage', which means it will charge from either a 110v or 220v outlet without a problem. So these days if it's a handheld device 99% you don't have to worry about the second type, and only have to worry about the first type. I suggest you look at the power adapter though and look at the fine print. If it does support dual voltage, it will show something like "100-240v AC" or similar.
Edit: in this case if it's a Note 2 I'm 99.99% sure that the power adapter comes with the phone allows dual voltage. So as long as your mom has the compatible physical plug to plug in on the wall, it will work fine.