The Life Cleric's Disciple of Life feature improves the effect of healing spells:
Also starting at 1st level, your healing spells are more effective. Whenever you use a spell of 1st level or higher to restore hit points to a creature, the creature regains additional hit points equal to 2 + the spell's level.
Does Disciple of Life apply to the healing provided by creatures summoned by spells?
For example, if the Life Cleric casts Summon Celestial and the Celestial uses its Healing Touch, would that benefit from Disciple of Life?
The same would presumably apply to spells such as Conjure Celestial (Unicorn's Healing Touch) or Conjure Woodland Beings (Dryad's Goodberry).