Normally. when you download a support package, you actually download the basic information needed for MATLAB to grab the the actual package, download and install it.
If you need to get packages for an offline computer, try downloading the packages according to these instructions using whichever internet you can get the best connection from. Afterward you should be able to transfer the resulting files to your computer. All you need is the Support Software Downloader on the machine connected to the internet and MATLAB on the offline computer.
