no
You can call the police and classify the 15 year old as a runaway. Of course you know this type of behavior can't go on so once the 15 year old is back at home then they should go for counseling and there are programs where the 15 year old will stay at a 'house' or 'facility' to get the proper care they need. Running away for a 15 year old is highly dangerous and worrisome for the parents, but then I don't need to tell a parent that. This child is out of control so get the police on it and have a master plan such as I suggested.
yes you can
no
It depends on where you live and what state or country you are in.
It is dumb for a 15 year old boy go to meet 25 year old woman to have an honest relationship with
Yes, but only if the 15 year old will allow it. You can't just go grabbing the 15 year old and laying your lips on him/her; that may be considered assault.
yes, she can
No. You have nothing in common.
That would kind of awkward.
im 15 im with a 20 year old its not bad because we love each other
age is just a number
NO! And the 19 year old guy should go to jail if he has done anything sexual with the 15 year old girl!