What we've done is we have taken Siri proxy, which is a proxy server that can add new commands and answers to Siri, and we used that to control lights. One of the new commands that was added was "Turn the lights on/off" and Siri would either turn the lights on or off depending on what you had commanded it to do. This can be especially useful to the elderly, as moving to the light switch can be very tiring for them, and as long as they have their phone with them, they can control the lights of their home from the push of a button. Below is a tutorial on how to install Siri Proxy, and Plugins. Although this content is in the procedure, here it is anyway:
Here is the video on how to install the plugins: