What should I Do?

Hey guys hows it going? Well, my dad had gotten engaged to a on and off again Girlfriend, they dated from about age 14 - 18 then again from about 20 - 22 and then his Girlfriend got married until they were in their mid to late 30's and my dad never got married. So up until about 2003. So then they started dating again because my dad had just split up with my mom who he had been dating ever since he broke up with that girlfriend. So anyways after dating (again) for only a few months they got engaged, I was happy because I really like her and she loved me almost like a son.
So upon the engagement they were looking into buying a home together. (My dad had been looking on his own anyways.) They found a home literally right around the corner from my current house. So my dad decided to buy it as a fixer upper. He bought it for $250,000ish and figured he'd put about another $150,000 into it. When I first seen the house I already had a bad feeling about it. But I said whatever I trust my dad will do a good job with it, and I'm sure it will be great!
From the outside of the house it looks huge, but the inside not so much. That's one of the problems. The current house (that we are renting, and have been renting for almost 6 years) is HUGE! and the house is a 2 Family. And that's a pretty good thing that the house is huge because we have a good amount of stuff. So anyways I seen the house today for the 1st time since I had originally seen it, and while the house is nice, it is still not great.
What I'm worried about is that my dad likes to live comfortably. He likes taking trips, having nice things, and all that type of stuff. I mean we don't own anything outrages or anything, but he just likes living good and being able to do things and have money in his possession.
This house is nothing special, he said to me today before I walked in "Son we have the nicest house on the block!" When I walked in I was not that impressed, or by the way he makes it sound not as nice as I thought it was gonna be, I wasn't expecting anything like EXTREMELY NICE but I wanted to walk in and have a smile instead it looked more like this:
I know the house isn't exactly done yet, but it still looks really small, the kitchen is one of the smallest kitchens I've ever seen, he had a fire place put in that looked horrible in my opinion, ugly, and took up almost 25% of an already small living room.
And to be honest, the only reason my dad wants to move is because he thinks that paying for the house we live in now is like paying for a house. When in reality, it's like only 50% of paying for a house. And I seriously don't think my dad really truly understands that. He didn't even know that you have to pay to use water! Even I knew that! And my dad takes a minimum of 2 showers a day, but for the most part 2 - 3. And he's constantly running water! He has no taxes to pay for this house, He's planning on putting in Central Air Conditioning and Heating into the house, which I heard is even more expensive.
I'm just worried that my dad doesn't know what he's doing and he's going to be spending all sorts of money that he already doesn't like to spend, it's just me and him, and he currently has a new girlfriend, he broke up with the one he was engaged to because she knew the house was putting him under a ton of stress and though she should live in her house until the mortgage went through, and he thought she was breaking up with him, so now he is back with the girlfriend he was with before her, and I hate her, shes controlling and a bitch (and she's my cousin from my moms side) oh yeah and did I mention shes kinda making him do the house the way she wants it done. Shes the one who picked out the color for my room, she chose red, I'm 17 and a Boy, and she said red is relaxing, I looked it up, its not recommended for a bedroom, because it's dark and can cause anger and stress. I wanted white walls in my room. But No she already had it painted. He bought the house in May/April and says it will be done in about a month, when it should have taken 6 months - 1 year. But he's rushing through it.
What should I do? Should I tell him that he was planning on maybe fixing up houses and reselling them and making money. Should I tell him maybe that's just what he should do with that house? I know he wanted to make it his own and stuff, but his new girlfriend had a huge say in it, maybe more of a say then me, and he already dumped her before for being too controlling.
While she may have a lot of money I don't see them lasting, and I don't see him being able to deal with this house by himself. What should I do?
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(Sorry for the long story)​

 

tl;dr. Use paragraphs. If you feel the house is to small, tell your dad to add attachments to it. They add space, and are good for the value of the house.