Can he contact his (female) cousin to greet her by phone?

No File Exists
Check below answers in case you are looking for other related questions:
He is being taught by a female teacher – what should he do?
His friend got to know a woman; can he call her to ask her to keep away from him?

No File Exists
Related Answers:
Warning and comment on the Peking Women’s Conference
Etiquette of talking to women
Is what he did to find out about his fiancée correct?
He is being taught by a female teacher – what should he do?
His friend got to know a woman; can he call her to ask her to keep away from him?

Recommended answers for you:
Men’s dress code
The seven sins that doom a person to Hell
Reducing the eyebrows by cutting them
Coping with wet dreams
Ruling on drinking whilst standing