RAW is NO
PHB, 192 for the HELP action states (emphasis mine):
When you take the Help action, the creature you aid gains advantage on the next ability check it makes to perform the task you are helping with...
Alternatively, you can aid a friendly creature in attacking a creature within 5 feet of you.
Saving throws are not Ability Checks or an Attack.
In addition, there are some character classes that do aid in such an activity. Namely, the Bard's Countercharm (PHB, 54)
As an action, you can start a performance that...any friendly creatures within 30 feet of you have advantage on saving throws against being frightened or charmed.