“I have been with my girlfriend for 3 years and we found a sperm donor so we could have a child. We had our son a year ago but I didn’t give him my last name. Now she is very sick with cancer, so my question to you is: how can I go bout giving him my last name and getting legal custody of him? Just in case something happens to her, I want to make sure that this matter is managed ahead of time. I live in Philadelphia, PA.”
You will need to consult with an attorney in the Philadelphia area, and asap – with your girlfriend – to get this all set straight. You need to do this while your girlfriend is still able to, because if she passes away with it not done, you risk the possibility of losing your child should someone challenge it.