This is obviously a concern, but I think personality has a lot to do with it.
I haven't made new 'friends' because I just don't want more of a social life. I am a pretty strong introvert; I am loud and friendly and boisterous, but spending time with people tires me out.
During the week, I get up at 6am, spend time with my daughter while I get her ready for daycare. Then, I go to work, where I am talking and laughing and having fun with coworkers all day while I work. Then, I come home, picking up my daughter on the way home. We go for a walk, she tells me all sorts of stuff, and then I make dinner while my wife watches her. We eat, get our daughter to bed, and by then it is around 8pm or so. At this point I am tired, and just want to relax, maybe read or watch TV a bit, chat with my wife, and go to sleep. There is no way I would have the energy or time to socialize on weeknights; I am all socialed out from work. The few times we do have plans during the week, I dread it because I know how tired and unsocial I am going to feel.
On the weekends, I am spending time with my daughter and wife. In the morning, I will make us breakfast and we will either play outside or go for a hike. We then take her home for a nap, and we do chores around the house. I always feel like there is not enough time on the weekend to get everything done.
I have a few close friends who live far away; we all play video games together once a week. I chat with my family, and between my nieces and nephews on both sides, there are a lot of video chats to have.
How is this a bad thing? Why do I NEED more friends than what I have? I am not sure what more 'emotional support' I need; I am a super happy person, always optimistic, and my wife is there for me when I need her (which isn't super often). I also can talk to my parents and sister if I needed more emotional support, or my two close friends if they weren't around.
I don't think your dad's issue is lack of relationships, he just sounds like he is an angry person. Is he retired? Being retired is a WHOLE different dynamic.
In fact, the biggest thing I feel I am lacking is ALONE time to work on hobbies. Before I got married and had a kid, I had all sorts of fun hobbies I did; I built airplanes and helicopters, I built robots, programmed games for fun. I like building and designing stuff, alone in my workshop, but I don't have enough time now to do it very often. This is a fine sacrifice to make, because I love my family and want to spend time with them, but it isn't like I am sitting somewhere lonely.
I am curious, however, if there is something you think I am missing by not having more friends. I certainly can't see it, because the idea of having more friends that I have to visit and see just makes me feel tired even thinking about it.