What do I do about a friend - sweet, but a complete idiot of a friend?

I have a close male friend and lately over the past few months I've noticed that he hasn't really been attentive or considerate of me lately. Don't get me wrong when we're together, we get along great and we have a lot of fun and he's sweet but any other time he's not really all that smart. For example, if we make plans on average every few weeks something comes up and we have to reschedule or he's always running late when I notice with all his other friends they don't deal with this with him.

Or he forgets that he wants to go do something with other firends and can't always fit it in his schedule so he asks me if I can reschedule or switch times or whatever. Although he does remember the little things, he forgets things I tell him all the time and remembers everything about everyone else.

I had a talk with him a couple of weeks ago about he's been inconsiderate and about other things he was doing that made me sad and he apologized and pretty much said he didn't realize he was doing any of those things but would think about it some more and figure out what he was doing wrong and try harder and since then he's been doing great it's just that he's still having issues being considerate about making plans and etc.

I have the greatest time when I'm with him and there's no one else I'd rather be around but frankly I'm tired of moping because he's a complete dummy and I don't want to have another "talk" with him so what should I do?