Vignesh, it doesn't quite help because my tab items are defined explicitly, the tab control is not bound to a set of items as its source. As a result, I can't use the TemplatedParent RelativeSource. My tab control structure looks like this:
<navigation:SfTabControl>
<navigation:SfTabItem>
<navigation:SfTabItem.Header>
// Header
</navigation:SfTabItem.Header>
// Content
</navigation:SfTabItem>
<navigation:SfTabItem>
<navigation:SfTabItem.Header>
// Header
</navigation:SfTabItem.Header>
// Content
</navigation:SfTabItem>
</navigation:SfTabControl>