Ranked Team Help and Advice, Especially with our Top-Laner

Once upon a time, a group of friends and I made a ranked team around 2 months ago. We are all good friends and know each other personally (except this one guy that we just met outside the game, but he's cool). We were all excited about making the ranked team and I assumed the role as captain since the others seemed to trust me the most and I kind of took it, too. Now you think this will continue to be happy, well think again. Only two of us are ranked, both silvers, two of them could be Silver V-IV if they learn minor things, and the last one... well below that. Our team have this issue and it's not with out teamwork, it's with one of our players and it's not the one guy that we just met, he's cool. We had an issue with roles and two of our players (who were all close friends of mine) kept bickering about Support. As the team captain, I had to choose which one of those became support. I decided to give one of them(the future problem) two weeks to show me and the team that he deserves support and after two weeks, I just made the decision based on who played better with the ADC at the time. He did not win the Support war. Now with a support decided, the future problem will be playing top lane, as it was his backup role and we all agreed that it will be fine. It was not like he was forced to suddenly play top, he played top numerous times, more than me and he did asked for it, so we gave it to him. Well, it wasn't fine. Our top laner wanted to play Crit-plank, EXCLUSIVELY, and during practice games either A) Lose lane horribly and refuse to go tank, thus forcing me (as Lee Sin or Rek-Sai most of the time, a.k.a the try-hard junglers, and usually ahead in terms of gold) to go tank or B) Through me camping, he wins lane and does nothing with the pressure that he controls top lane, thus wasting some of my time up there. When we lose games, we would talk and discuss why we lost. When we discuss about our top laner's play and discuss what we could have done better, he flips and starts screaming at us as if we killed his family. We try to bring up some decent points like warding (never wards lane and acts cocky about it) and grouping mid with us. I'll admit, at times we do act harsh to him because he tends to piss the team off with his attitude and his play, but at certain times, his behavior is inexcusable. The team have talked to him, sometimes kindly and sometimes with tough-love, to take the game more seriously, try to listen to us, and maybe try out some other champs like Lulu (since he loved her and played support a lot beforehand) and expand his champion pool. We even mention that he should practice on his own time and refuses to do that. Afterwards, we decide to practice with him, but he doesn't even want to practice or just goofs off with Crit-plank. Fast-forward to this week and I'm vacationing and tried to talk to the others about team comps because I want to practice when I come back. As the three of us (the other two were gone, I can't blame them) were discussing team comps on Skype, the top laner keeps saying that "I want to play Rengar top-multiple" times as he started to like top lane Rengar. Now here's the problem, he "plays" (doesn't even own him, wtf) Rengar top-lane exclusively and this pissed me off. I came up with 3 team comps that had champions that the five of us were somewhat comfortable with and 2 of them were shot down because of his demand for Rengar, as he doesn't fit well into the other two comps well. I felt like shit after the Skype chat because I want us to do well and I spent time thinking of potential comps that we could play and the top laner shot it down. We have not practiced for like a month as 5, only practiced at most as 4. The other 3 I have great synergy with and I believe that they have tons of potential in the team, good news for the jungler like me, they just need to expand their pool which they're doing even now. The top laner is being exclusive to one champion and this is a huge hindrance to the team. I don't want to kick him as this is a ranked team of close friends and we're not trying to go to LCS here, but the other 3 want to do well and it's unfair to them that their hard work is being thrown over the bridge because of one person. All I'm asking here is for any help and advice from this community. What should I do as the captain of this team? Also, I shall apologize for the essay as this really helped blow some steam and I couldn't really think of explaining this anything shorter. Have a nice day on the rift and nerf Irelia rito.

From, a try-hard jungler that wants his team to do well