the RED.tabs component is a custom component created for Node-RED. It has nothing to do with the jQuery UI Tabs component.
There is no api for disabling a tab (by which I assume you mean leave the tab in place, but don't let the user select it) - it isn't a feature we've needed in the core of Node-RED so no code has been written to support it.
You can fully remove a tab using node.tabs.removeTab("node-plotly-tab-chart");