1-- affinity = a natural attraction or feeling of kinship
2-- far-reaching link = emotional/mental connection to the distant personal past
3-- talking about your past with siblings recreates those warm feelings; it confirms the reality of your former life and keeps them clear in your mind.'
4-- it is better to turn to your parents or children ('up and down') than to your brothers or sisters ('sideways') for help.
5-- Mere mention = simply their names. Many people react emotionally when they hear a sibling's name.