Firstly welcome to this forum. Plenty to learn as you are well aware as we all do. Firstly we don't know your family Hierarchy nor your level within, what are the rest of the family saying/suggesting?
As Fred suggested this is a local argument and while I appreciate the implications and learnt many years ago to steer clear, hence 40 mins drive away from the 5,000 relatives. (perhaps one can suggest this option to your soon to be outlaw). Too far for for a simple tricycle ride but close enough for us to visit when we want.
Is this new member of the family conversant with our local culture and the ramifications of living within the family group? Perhaps a little cajoling may change his mind? Only a thought if he is a little green. BTW what does your lovely lady say with regards to all this? She and her siblings hold the power.
Well good luck and please keep us posted.