Am I overrreacting??

My mom has this little “situationship” with a younger guy. He’s 24-25 and she’s 46. The age gap doesn’t bother me, but it’s the fact that this guy is known for flirting and getting with every girl. I’m 20, but while I was in high school, this same guy tried getting with all of my friends, and even knocked up our friends 16 year old cousin (and went to jail because of it.) He worked at a mexican restaurant in town which is where he met my mom and they’ve constantly flirted and hung out up until he got a girlfriend a year or so ago. Also right around the time he got his girlfriend, his mom died, so I feel like after that he latched onto my mom even harder. During that time she was giving him money and buying him food. Even after meeting my mom, whenever my friends and I would go to the restaurant he would also be flirting with me (knowing who my mom is.) My mom gets mad at me whenever I bring up him hitting on underage girls, knocking them up, etc. and defends him for all of this. It’s not the age gap that embarrasses me, it’s just who the guy is. The other night I came home after work and he was parked in my spot in front of our townhouse where my mom and him where leaning against his car talking. My mom told me to just park on the street. I truly thought that was so disrespectful that she couldn’t have told him to move onto the street? They also ended up leaving for hours and she didn’t even take her phone with her. This also bothered me because she’s always getting mad at me for not communicating my whereabouts with her, but she can’t do the same for me? My grandfather, her dad, is going through some major health issues where multiple times in the past month we have gotten calls from him to either take him to the hospital or to meet him at the hospital, if something would have jumped off nobody would have been able to get in touch with her. I think this really bothered me because when I was 13 and home alone I ended up getting these major chest pains and wasn’t able to breathe, I literally though I was dying. I tried calling her at a party but she didn’t have her phone with her so I had to call 911 and go to the hospital and sit by myself until my uncle was able to get in touch with her. I’m just angry and grossed out by the situation but I feel like everyone thinks i’m overreacting and no one will listen to me about this