My most basic level of commitment applies to everybody. That is, I will do what I say I will do.
Now, what I say I will do for someone depends on which concentric circle of relationship closeness I have with them.
My innermost circle is FAMILY. Family includes blood relatives as well as those I've "adopted" into my "family". I have blood relatives who are not in my "family", including my brother. Unfortunately, we had a falling out and we're just not that close anymore. What would I do? I was talking to my dad this weekend about his kidney's which are functioning at 40%. I told him I've got one he could borrow. I was joking, but also I was not. It is something I would do for "family".
The next circle out is TRIBE. These are relatives and friends whom I would help out when needed. But I wouldn't go exceedingly out of my way to help them. My brother is in my tribe.
Then there is everybody else. I treat them how I want to be treated. But I don't promise them anything.
Me: 48 - Married, straight, male
Shiela: My wife.
Suzanne: My FWB
Adam: Shiela's LDR