The house was being maintained up to 2020 at least, as shown in the attached satellite images.
You can see the garden in March 2020 is about the same state as in May 2018 (i.e. maintained), but then some time between March 2020 and June 2021 was left to grow over in a really bad way (compared to the neighbours' for example).
So, a fair conclusion from this was that somebody other than NM maintained the property between his death in April 2019 and that March 2020 satellite photo. Likely needing keys.
Interesting you can see (top left) between May 2018 and March 2020, the small trees/bushes in the pathway between the house and the fence have been removed. But then in the most satellite recent shot, which was taken October this year (the 3D Google Earth one) you can see they are back.