My friends boyfriend?

My friend loves her boyfriend with all her heart but she told me that when they're kissing he is kind of forceful. He's really strong. If she doesn't want to kiss him and turns her head away he pushes her head towards his. She also said sometimes he will hold her down and kiss her. I've met him before and her and I both agree he is very sweet and nice but I was wondering if I should worry about this so I can tell her something. I know she loves him dearly but it kinda makes me worry. Should she talk to him about this? Thank you