If you want to look at this is on-the-job training, a learning experience, and opportunity to develop and prove your SEO skills, than getting paid $14.00 an hour to go to school is a really good deal.
But that is at the opposite end of the spectrum of a real job, and it's important for you going into the relationship to keep that firmly in mind.
As a "student", you and your employer can make up any relationship you want, and the ambiguous nature of the learning experiences will always balance off the other side of the equation.
But never forget that it IS an equation, and there is always a balance.
Here's some reality:
$14.00 / hour X 40 hours a week X 4 weeks a month = $2,240 / month, minus 22% for taxes, FICA, etc... = $ 1,750 take home pay.
Unless he is paying you as a Contractor, in which case you are working for about $8.00 / hour after the smoke clears from paying your taxes and both sides of FICA, etc...
There are several things about your post that have raised some red flags with me, and it is my hope that you do not have to learn the lessons that I have learned "the hard way" which is almost always money. Mistakes in business are punished as financial losses, and while they are painful they are also "gifts that keep on giving" because actually the best way to learn a lesson from a financial mistake is to have an extremely clear recollection of the pain. If you forget that pain, you risk making the same mistake again.
So I am divided at this moment in my desire to help you to avoid that pain. The "other side" to the argument is that the earlier that you feel it, the more money you will make later as a result. So with that in mind, here's where I would be if I were presented with your situation as you described it.
1) Looking for a $14.00 / hour job has forever pigeon-holed you as that level of employee. If the owner makes you feel otherwise (due to his charisma, etc...) well maybe that's how he got rich.
2) Accepting any kind of job at $14.00 / hour permanently limits your upward mobility. They will ever pay you $30.00 an hour, even if you deserve twice that amount.
3) There is an "opportunity cost" to taking any kind of job. Once static momentum sits in, you are much less likely to move on and into a better situation. You will have to overcome your own comfort and your own fear in order to do so.
4) It is always a bad idea to let the failure of someone else's previous relationship form the foundation of the new relationship with that person. You become in extension of that previous individual and they will always treat you as if they are doing you a favor for being there, given what the "other you" did before you got there.
5) If Mr. Charisma knew so much about business, he would have taken responsibility for the fact that he hired someone to do SEO that did nothing. Where was Mr. Charisma when the "nothing" was happening. It was his responsibility to know what Mr. Previous SEO was (and was not doing), and it sounds to me like he still doesn't take responsibility for being a poor Manager.
6) It was a bad idea to share any of this with you, as it exposes what I just said, above.
7) The fact that he DID tell you, says something about him and,
8) Chances are good he will repeat his mistake(s) again, only this time you will be the one he blames. It's your turn.
9) And you are volunteering for this.
People value things based on what they pay for them. If you pay nothing, it's worth nothing. If he pays you little, then that is what you are worth. You name a fair price on the high end, he counters with a fair price on the low end, and you meet in the middle and then you have a relationship based on mutual respect. You grovel and whine for a mediocre job and he'll expect gratitude each time he kicks you. People respect people that name a price and are willing to WALK. People that are willing to WALK over what might be an insignificant difference in price are also willing to WORK once that price has been paid. It has to do with the certainty of your own value, and that I think is your primary problem. If YOU don't know (and you don't for obvious and understandable reasons), then you cannot possibly convince someone else.
Finally, there is the cost of finding someone else Mr. Charisma finds acceptable. You have a certain level of (for lack of a better word) "desperation", and so does he. It's no accident that the guy that came in to apply to be the assistant chief bottle washer suddenly is escorted under armed guard for an audience with the King. The King is desperate, there is unrest in the forest, there is trouble with the trees. and the timing of your arrival could not have been more fortuitous. You've arrived just in time to save the kingdom, and there is value in that. My point is that "value" in this case means money. The fact that you got out of bed that morning instead of sleeping in means you've already given him value. The fact that you breathe is of value to him. He can call you on the phone any time he wants to, and you'll take that call. That also has value.
My point, and hopefully you take it in the spirit in which it is delivered, is that you need to KNOW all of this, down to your very marrow, otherwise when the negotiations get tense, you betray your own sense of self-worth and (frequently) not only do you not get the job at a reduced-rate, you don't get the job at all. And (here's the pain part), you've created that dynamic yourself. Or, at least in my case, I created it MY self. Your experiences may be different, but I doubt it. I read a lot of anecdotes from other self-made people, and much of what I've learned the hard way has also been learned by others "the hard way", and again, I'm ambivalent about whether or not it's really a good idea to try to "nudge" you off those catastrophic failures, given the direct financial value those lessons have had in my own life.
It's late. Gotta run. Good luck.