Are they old enough do kids have minds of their own?

thank you for people who answered below about parental alienation, and how my hubbys kids only want money and no contact.... that hubby should send cards and ect. but one question i wonder if you know... since hubbys kids are 13 and 15 and they never return hubbys calls or they arent ever around or whatever excuse. Hubbys daughter has a cell phone and there is plenty times they are alone to use the phone, you can be honest. i dont mind. but they are old enough to call on their own right? they do other sneaky things, so when hubby calls if they really wanted to see their dad which they say when they randomly see him whwen they are forced to . but completely ignore him unless asking for something. sorry rambling. but they say theyll call and NEVER do. if they truly cared theyd at least pick up the phone to call once a month right? if they had an inkling of compion they make that call? or are they trully brainwashed by alienation adn just dont care?