How much health will a Life Domain cleric regain from the Blessed Healer feature using the Mass Healing Word spell?

Question

This question could loosely be considered a follow up to "Can Goodberries heal a Life cleric when consumed by another."

How much life would a level 6 Life Cleric with four party members gain from the Blessed Healer class attribute with a casting of Mass Healing Word?

Blessed Healer

Beginning at 6th level, the healing spells you cast on others heal you as well. When you cast a spell of 1st level or higher that restores hit points to a creature other than you, you regain hit points equal to 2 + the spell’s level.

Mass Healing Word

As you call out words of restoration, up to six creatures of your choice that you can see within range regain hit points equal to 1d4 + your spellcasting ability modifier. This spell has no effect on undead or constructs.

If the Cleric casts Mass Healing Word, targeting each of the 4 party members, how many times would the Cleric gain HP equal to 2 + Spell Level?

Taken further, would the Blessed Healer effect be prevented if the Cleric targeted himself with Mass Healing Word, in addition to the other 4 members of his party?

Answer 1

If the Cleric casts Mass Healing Word, targeting each of the 4 party members, how many times would the Cleric gain HP equal to 2 + Spell Level?

I would argue only once, because the trigger for Blessed Healer is "When you cast a spell...". You only cast one spell, so you'd only get healed once.

Taken further, would the Blessed Healer effect be prevented if the Cleric targeted himself with Mass Healing Word, in addition to the other 4 members of his party?

That's easier to answer. I'd say no, the effect is not prevented, since casting mass healing word to heal at least one person other than yourself clearly satisfies the requirement for Blessed Healer.

Answer 2

Blessed Healer would trigger once whether you target yourself or not, unless you were the only target of the mass heal.

Another way to read the ability would be "When you cast a spell... that restores hit points to at least one creature other than you..."

Even if you choose yourself as one of the targets, unless there were no other targets of the spell, Blessed Healer would still trigger, because you are still affecting creatures other than yourself.