Am I Being Too Sensitive About His Language?

As-salamu alaykum sisters! I'm a 25-year-old woman, and I've been in a long-distance relationship with a 25-year-old brother for about three months. We've met a few times in person, and overall he's a good guy. But I've noticed he often uses offensive words and likes to imitate accents, which feels disrespectful even though he says it's just for fun. I really dislike hearing hurtful language because I believe our words reflect our character deeply. Those accents make me quite uncomfortable too. I'm wondering if I'm overthinking this. I grew up around men in my family who speak gently and kindly, always trying to follow the Prophet's example in their speech. This is what I'm used to, and I've never accepted this kind of behavior before. Some friends say this is just how guys are and I shouldn't make a big deal since he's a good Muslim. They say I'm being "too sensitive." It bothers me because I've been called a "stick in the mud" for not laughing at jokes I find inappropriate or for speaking up. I've gently mentioned this to him, but he finds it funny and sometimes repeats it to annoy me. Before meeting him, I wasn't really sure about marriage, so maybe I'm making excuses to avoid moving forward or searching for some "perfect" guy as my friends say. For me, I just want someone who reflects the Prophet's character, especially in how he talks and treats others. Am I being too dramatic or unrealistic? Has growing up with such wonderful men set my expectations too high? I don't want to share this with my siblings because they like him, and I don't want to ruin their opinion if things continue. So, I'm asking for your advice here! JazakAllah khair in advance <3