I have a legal, ethical and moral dilema.

I'm not sure where to start, so I will just write it as it comes.

Background:
I have a friend who met a man, now aged 26, they got engaged, then he found out he had testicular cancer. He called the relationship off, but she stuck by him. They got back together, but not re-engaged, he had alot of debt that she did not what to inherit. Anyway they decided to have a baby. When she was about 12 weeks along he went back to work, he had not been working for over a year due to his cancer and ongoing battles with pain. He was working long hours and their relationship was getting rocky. She then started hearing rumours that he was having multiple liasions with other women. She choose to ignore alot of these rumours until she heard one that she knew was true and then decided to leave. He kept denying the accusations, then she heard about this 15yr old he had hooked up with. Before long the 15yr old moved in with him. The 15 yr old is registered for centerlink benefits, but they have not disclosed the true nature of their relationship. My friends couisn has called centerlink to spill the beans, so to speak. Not sure of what has happened. This guy has not contributed anything towards his baby, he only has to pay $10 week in child support, which he has not paid yet. It is so low because he has not worked. He only just submitted his last 3yrs of tax returns to get the goverment stimulus bonus, he got back $5000 so he and 15 yr old went on holiday to NSW.

Anyway my friend just called and told me 15 yr old is now PG about 12 weeks along and engaged. My dilema is I'm a nurse and there is legislation about having to report any suspected cases of sexually abuse that you come across as part of paid or voluntary work.
I have not come across this info via work, but feel that this man is taking advantage of his position/situation. My friend is denying him access to his child because he has not contirbuted anything towards his child. He is not paying because she is not letting his 15yr old GF to have access to his child.
Personally I think my friend was stupid for decided to have a baby with him in the first place. I think he did not truely beleive he could have children, esp after having a testicle removed and undergoing chemo. Towards the end of the PG he started making accuasions about the baby not being his, but there is no denying paternity looking at the child. I think he has used his current position to take advantage of this 15yr old, to make her beleive they will be together forever, despite him telling his ex that he thinks he will be dead in 2 yrs. That he is now speading his seed, so to speak since he does not see himself being around for many years to come. That by getting this 15 yr old PG he will have a control over her, she will not be able to leave even if she wanted to. He was never physically abusive towards my friend, by did punch walls, I think there is potential for physical abuse. He spent far too much time drinking. He lives in a 1 bed room un-insulated converted farm shead, which has mice and ****roaches, the house on the property is not much better, currently his transgender father/mother lives in.
The 15 yr old mother seems to condone the relationship, though have heard horrified about PG. Originally his mother did not condone the relationship, but since the PG has changed her tune. My friend has allowed the grandparents access to her child, but now re-evaluating the situation. They have only contributed a little towards the child.

I know his name and address and her first name. I was thinking about calling crime stoppers and leaving an annomyes (sp) tip. I felt this way from the beginning, but decided to leave it alone, it wan't my place. The 15yr old mother knew. My mum told me to butt out.

Also forgot to mention, this will be his 3rd engagment and 2nd baby. Never married.

What do you think I should do?