Well the easiest way to avoid dealing with firewalls and dynamic IP addresses and other things that make it difficult for you to connect directly to a device inside their home is to use a camera that can be accessed via a cloud service. Think Nest, Dropcam, etc.

But I guess I’d consider first what your objectives with the camera truly are, and what kind of monitoring you’re really looking to do. You can’t put them in every room of the house. Given that, does it make more sense to set them up with a tablet or Facebook Portal or something like that where you can video chat with them? As opposed to more of a surveillance-type setup?