playing ppl who kick the **** out of you are always fun and very helpful. Figure out why they are kicking the **** out of you, and improve. Also, i doubt the only ppl who play smash near you are you and your bro, they might be the only ones within a 5 minute drive, but that's not anything. You might have to look out a radius of 30 min drive to find ppl who are better than you, but it will help. You might want to check the regional zones under the tournament section to find players near you (in addition to tournies near you). But the best thing you can probably do is to stop playing against CPUs except for training very specific things (i.e. waveshining, etc...) but never for general gameplay. Play against your bro a bunch. even a human who is not good is better than a cpu because they think and change things.
Edit: oh yeah, for practice, i go in training mode, spam a bunch of lasers around, practice drillshining/ waveshining. sometimes i rubberband a controller's l button down, and shffl into it's shield until it breaks, then repeat. I also practice other random stuff like firestalling, multishining, illusion edgehogging, edge wavedashing, etc.