Hi Lucan,
For the outdoor, I would use the drone and take pictures of the house from different angles. Then using a
photogrammetry app (e.g.,
http://ccwu.me/vsfm/ with this
tutorial to generate a mesh with meshlab, or dji drone deploy
https://www.youtube.com/watch?time_continue=436&v=q3wXggCqY_8), you would be able to get nice looking exterior (like google Earth 3D).
For indoor, the most simple and robust option is with Google Tango on an Asus ZenFone AR (with
RTAB-Map,
Google Constructor,
Open Constructor or
Matterport apps for examples). Another consumer option is to buy a
structure sensor for iPad with the app from Occipital.
Without buying anything, using RTAB-Map windows
binaries with a laptop/surface4 with one of the Kinects (xbox one will be more accurate) could work (assuming you can make the kinect running on battery), but for small rooms and with careful scanning to limit the localization drift (following the scanning tips from
here).
Hope you will be able to show your house to your grandma with one of these apps!
Mathieu