I would certainly think so. But it turns out to be surprisingly hard to quantify.
(I'll just talk about lobbying, not political donations, which is a related but separate issue.)
The organizations with the most lobbying spending are the US Chamber of Commerce (politically right, but not necessarily representing the very wealthy) followed by the Open Society Policy Center (politically left, but not necessarily representing the poor).
Most lobbying comes from industries of some sort (e.g. realtors, hospitals, farmers, coal, manufacturing, unions, education, etc). The legislation these groups favor will often disproportionately benefit the rich, but they tend to benefit rich and poor alike within that industry. For example, the farming industry may favor subsidies that benefit both poor and rich farmers.
As an example of industry working against the wealthy, the life insurance industry is the main group lobbying in favor of estate taxes (a tax which only affects the wealthy).
I'm not aware of any lobby groups that are specifically for the interests of the wealthy. However, politically right groups largely fill this role (the distinction being that right-wing fiscal policies are broader than just cutting taxes for the rich).
I don't think so. Poor people have no lobby. Families have no lobby.