Ties of kinship

[SistaSista]

Salam Alaykum Brothers and Sisters,

I have a question, that I hope you can shed some light on.

What does 'maintain the ties of kinship' mean to muslims?

My understanding of this phrase is to be kind and keep contact with family ie Mum, Dad, Brothers, Sisters, Aunties, Uncles, Grandparents and cousins, and if they are non muslim, I should treat them in a worldly manner.

If anyone can elaborate on the term 'worldly manner'?

How should one deal with the non muslim family and are there certain circumstances that make it okay to not contact them?

I read that muslims should not take kafr for friend, would this mean to disolve friendships?

If possible please can you support statements with authentic hadith.

Thanks
SistaSista