Disney benefits from the millions of tourists that visit Orlando each year. Without these tourists, Disney Theme Parks would go out of business. Therefore, it would be a very generous gesture for them to raise as much money for the Orlando shooting victims as they can. In short, yes, Disney could raise a lot more money for the victims.
I don't think Disney is directly involved in this tragedy at all. What they are doing to try to raise money for the families is a great effort, and I don't think they could or should be asked to collect more money than they already are. We should be grateful such a large company is already helping out with the problem at hand.
It is not really Disney's responsibility to raise money for dead people. They raised what they raised and that should be enough. People have some weird need to place the onus of care on giant corporations that they otherwise talk trash about and babble about how horrible they are all the time.
Disney could certainly raise money for the victims of the Orlando shooting, but any money would be pure charity designed to help people. Disney is not obligated to give money to anything because it happened close to Disney World. It is a generous act to give anything to the Orlando victims and their families. All help should be appreciated, not judged.