Gabrielle Giffords is literally none of those things. Yes, she is now disabled. She has trouble expressing herself as most people can. She has trouble walking, talking, and holding a conversation. This does not mean that she is any less intelligent, or that she is any less of a person.
If she's basing her arguments (via her husband) on the fact that she happened to get shot, and is therefore now biased against guns as a result, then I would say that this makes her argument less intelligent. The gun, an inanimate object, did not shoot her by itself, and should not be blamed. If she had been stabbed in the head instead, would she still be trying to take guns out of the hands of law-abiding citizens? Heh, I doubt that she'd even go after knives in that case. Why is that?
It's not that I don't understand how a person's emotions can overwhelm their intellect, especially after having experienced a traumatic event and debilitating injury. But laws must be made on a rational basis, not an emotional lashing-out at inanimate objects.
Mark Kelly and Gabby Giffords had a very large, very important part of their golden years together stolen from them by a criminal with a legally-obtained pistol. Their opinions may not match yours, but they know first-hand the dangers of America's mental-health problem and the problems inherent with the easy and cheap access to firearms that we have today. They have lost a part of their lives together because Loughner was able to legally acquire a concealable, controllable, and deadly weapon.
That's too bad, but I don't see people going after alcohol for destroying the lives of thousands every year, for example. Our justice system barely even punishes drunk drivers, but nobody cares. And on the average about 700 children lose their lives in swimming pools every year (based on government statistics), but nobody appears to be interested in banning pools. At least Giffords and her husband got to live to adulthood and achieve more than most people could ever dream of--in contrast, nobody (publicly) gives a crap about those 700 (per year) children except for their families, of course, who suffer in private because their loss does not serve an agenda.
I would even go so far as to say that his opinion may carry slightly more weight than yours.
Actually, I would say that it carries less weight. There is a reason surgeons generally do not operate on members of their own family, for comparison. It's a matter of avoiding excessive emotion that could understandably cloud their judgment, and the same goes for the biased anti-gun arguments of the victims of shootings.
