I know of several people who have had their houses burn down because of an ICE car deciding to catch fire in the garage. Hyundai has recently recalled almost a million vehicles because they tend to catch fire while parked.
https://money.cnn.com/2015/10/27/autos/gm-recall-fire/
As someone else mentioned, I wasn't trying to argue either car catches fire more or less. The parent was suggesting ICE cars catching fire while parked practically never happens, when millions of ICE cars in the last few years have been recalled for such things. Lots of people have had their houses burn down from ICE cars being parked inside. A parked car catching fire isn't something new to battery vehicles.