Tenant's liability for damage to the home

Questioner

My son has owned a home since October 2018. After his girlfriend moved in with him, the relationship broke up; she fell in love with someone else. A friend who was looking for a place to live rented a room (or bedroom) from my son, with the entire house at his disposal. A properly drawn up lease agreement stipulates that the tenant must also compensate for any damage they cause. He is also properly registered with the municipality. My son has home and liability insurance with Reaal. His friend has liability and contents insurance with Centraal Beheer. Last Friday evening the friend caused a fire by not properly extinguishing a candle. My son's home insurance won't pay out because there's a lease. Apparently, the tenant had to take out a separate, additional home insurance policy, which was completely unknown. Can he hold the tenant liable for the fire and soot damage, including to the building? The walls, ceilings, windows, and window frames are all covered in soot and need to be cleaned and repainted (this happened just last year when my son bought the house). The terms and conditions of the tenant's liability insurance with Centraal Beheer do mention rental properties (sections 4.11 and 4.13), but they seem more like Chinese. Could you please take a look and help us? Thanks in advance!

Questioner

Because the risk of damage is increased by (sub)letting, the buildings and contents insurer must always be notified in advance. This is usually clearly stated in the terms and conditions. Your son can hold the tenant liable for the damage because he made a mistake by not paying enough attention.