There are really stable aluminum boats out there. The most stable, IMO doesn't have a deck front or back. I currently own a 14' stick steering boat. It's in the barn needing restoration. If it were a longer boat and had trim on the motor, I would likely never have bought anything else to fish from. The Xpress that I just bought is absolutely stable, but there are decks to step up and down to. On a stick steer, not having decks, the boats center of gravity is lower which makes the boat more stable. Mine is only 44" wide on the bottom but it is very stable.

IMO, the best boat for someone who has stability, mobility, or balance issues is a stick steer. You never have to leave the seat. Drive where you want to fish and fish. Just get one with power trim or it will beat you to death on choppy water.