I have had two that died before 8 years old form various cancers. The cause is probably poor breeding practices. The breed was virtually extinct less than 100 years ago and with the high price of the dogs the incentive has been to try to mass produce them. My neighbor has two that are now over 11 years old and still pretty healthy so my next one will be from his breeder.
Wow. It’s amazing that your neighbor has two Bernese that are over 11. If I ever get one - I want one from that breeder too!