Has {s,}he tried other browsers? I vaguely remember that in Firefox or Chrome, memory for a tab is kept together (tabs don't stomp on each other's pages) so the OS will naturally page it out when you haven't looked at that tab in a while.
This might not be true but I thought I'd make the suggestion.
Firefox remembers your tab icons and names between sessions but won't load the pages unless you interact with that tab. Most folks with 150 tabs open never look at more than a handful of them.
Note that pinned tabs will always be loaded as the assumption is you're using them for chat or something similar which needs to be loaded each time (messenger.com, hangouts.google.com, etc).
This might not be true but I thought I'd make the suggestion.