Obviously I am not invested in whether or not you decide to continue playing the game, but I think some of your ideas are assumptions and not necessarily accurate.
The reason for this move is to hide from the father. They are scared for their lives. All it took was the MC even slightly standing up to him for him to beat him up. If this is typical behavior from the father, fear is built up over years. It is common for victims of abuse to stay silent for fear of repercussions. Like a phobia, it can even be irrational, but the fear prevents action nonetheless.
They never called a lawyer. Both the mom and the MC are afraid of what the father might do if they were to call one. If Richard finds them, having called a lawyer wouldn't matter. They are worried he'll kill them and erase evidence of their murders, in which case having a lawyer does nothing for you. Again, they are acting somewhat irrationally out of fear; they aren't thinking about restraining orders or anything like that: they are thinking about not wanting to get hurt or die.
Do you know a lot of mob bosses? What makes you think none of them invest in the stock market? Wouldn't having more money provide more potential power for a mob boss? Couldn't a mob boss have people who know about the stock market work for them? If they did, those "employees" would be under the same threat as anyone working for the mob: if they make too many mistakes or they make mistakes that are big enough (damaging enough), their lives would be in danger.
How much money do you imagine Richard had before losing a lot of it? If he had US$500 million and lost US$400 million, there would still be US$100 million: plenty of money to have henchmen still working for you.
Again, it's strongly implied these are regular victims of abuse. It's also strongly implied that they are all afraid of Richard. (Well, not Liane, but she doesn't live in the same house, so she probably hasn't been subjected to the abuse. At a minimum, the amount she may have experienced is probably extremely small, especially in comparison to what the MC and his mom have had to endure.) When people are full of fear at that level, they often react in ways that seem illogical or unprompted. Their brains are likely operating mostly in self-preservation mode, not in structured and analytical thinking.
As one might expect, more explanation is provided as the game progresses. While I understand you can only base your opinion on what you've seen so far, there is more to the story than what you've described. Still, one job of any storyteller is to capture the attention of the audience. If this game hasn't impressed you so far, clearly Lemonkey hasn't succeeded in your case.
I believe this is a flawed assessment of the story's characters. The MC isn't lazy, but lack of motivation can be caused by a lot of things. I believe a big part of this stems from returning home to the same situation he's seen for so many years: mom is afraid to do anything against Richard, which means he'll walk all over her. After moving into the apartment, the MC does get motivated to give his mom a better life, and he gets a job at a local gym. It's not plush corporate employment or anything, but I believe this shows the lack of motivation gets overcome.
As I've already mentioned, the mom is scared. I don't think we know if he's ever physically abused the mom, but given how he beat up the MC, I assume she's also been beaten. At a minimum, clearly he's abused her psychologically: the mom doesn't think she's attractive, she doesn't feel like there's anything left for her in life, etc. I honestly think the only reason she's holding on to life is for the benefit of the MC. Without him, sadly I think she probably would have tried to kill herself.
I don't think the cousin is just a drunkard party girl. Based on the conversation with Liane after the aunt shows the MC to her room (and the aunt's behavior afterward), there are deep family problems for her as well. We don't really know the full nature of them, but I believe her drinking / attitude is a coping mechanism for her. Her own father seems to be out of the picture: the aunt is clearly unhappy in general, and Liane uses time with the MC as a kind of escape from those troubles. I think she feels like he's the only one who can (or who will try to) understand her; he seems to be the only person she really trusts. Like a lot of people with bad home lives, they find drugs or alcohol provide a temporary escape. They may not really consider long-term effects.
This is kind of my point: the reasons aren't logical; they are driven by an irrational fear created over years of abuse and manipulation by Richard.
Whether or not you decide to play the game again, I hope I have been able to help you at least understand more of what's going on in the story. It still may not be to your liking, but there are reasons for what's happened, even if they aren't rooted in logic.
