My niece by marriage is about halfway to becoming a mother later this year. That means I will be a Great Uncle. I'm 43!!
And while I'm still reeling from that, Best Beloved tells me that the Swedish prefix for 'great-' in this context is 'gammel', which just means 'old'.
I already wear a cardigan from time to time. I may have to invest in a shawl and some half-moon glasses too.