This is a pickle
The thing is that if he realise that he can upset you and drive you and your daughter appart, that is exactly what he will do. And so manipulate her. Your daughter does not sound like the type of girl that would spite her mom and bring home a bad boy, kwim? So she must see something in him that atm you are not getting, right? So why not be as nice a possible, not in a brown-nosy kind of way, but in a interessed in who you are kind of way. Invite him to dinner, alot. Be open about their relationship. Get her to tell you what they have been up to, not prying, but as easy conversation. Don't know if I am coming accross exactly as I would like.
I would start to worry if her behaviour change. And I think you will notice that very quickly, IF something change. HOPEFULLY it's just puppy-love, one month in, next month out.
Great job on him lying to her. And don't feel bad, but I would not like the idea of my precious angle dating a man-beast that has a thing for swatika's!!!
A gf of mine had once told me a very, very true thing. As hard as it is to accept, it's soooo true:
When you are in love, you live in a bubble. Her her case a Mr N-bubble. You are not seeing "outside" what is real and what is happening, because you are in this bubble. No matter what your friends tell you, or what your mom tells you, this bubble is your reality. Only YOU have the power to burst this bubble and see what is really there.
In other words, only she can be the one who decide that he is not for her. Sometimes it's easy, but sometimes it comes with buckets of tears. Just always be there for her and let her know that no matter what happens, you will not shun her.
I think it's still a good thing that she is seeing all her friends.
I don't know what else to say, except good luck

If all else fails - polish your long-range rifle

PS. Please God, don't let MY angle grow up this fast!!!!