Hi @Betty123 !
Hope you are well. I think you are being a good friend and a concerned friend. Having these thoughts and apprehensions about your friend's partner makes sense if you really care for them and it's natural to be defensive. It can put you in a tricky spot however if your friend does not see these red flags It can make for an uncomfortable conversation. But it will be an important conversation to have non the less. Have you considered raising your concerns with your friend and seeing how she takes it?
EDIT: I just read up on your replies to the other comments, It's good that you spoke up and that your friend was able to see your point of view. I'm glad you were able to have a mature conversation without things going the wrong way.
I hope things on your side have been going well, and feel free to share with us if you need to get anything else off your chest!