capitalization question

[cowgirl65]

I have a question over capitalization of titles and things used as titiles but aren't

I know earned titiles are capitalized: Sister Agnes, Brother Cadfael, Dr. Merar, Professor Snape

It's words used in place of names that I'm wondering about.

"Hello, Dad," should be capitalized, but what about "hello, doctor?"

one of my characters in canon uses a lot of terms of endearment: darling, honey, lovely lady

I don't think those should be capitalized, but I'm not sure

He also puts 'brother' in front of his siblings' names, i.e. brother Nick

when I capitalize that, it makes Nick sound like a monk to me

any ideas?

[Shadowknight12]

My contribution to the topic: http://www.english-grammar-revolution.com/capitalization-rules.html (thank you, BronxWench, for the page)