Ok, this moveset is mainly for doubles as a healer. I don't know how useful this Pokemon will be for singles though.
Ev's: 252 HP/252 Def/4 Spe
-Leech Seed/Synthesis/Giga Drain
Floral Healing is quite obvious. To heal your ally with priority.
Next, either Leech Seed or Synthesis or Giga Drain. Synthesis and Giga Drain will get priority due to Triage. Synthesis to recover bulk of HP, Giga Drain for healing as well as priority damage and coverage. Else Leech Seed also works though not priority.
Drain Kiss for priority damage as well as STAB. This move works well for Pokemons who are weak to fairy and does fair chip damage for others.
Substitute for protection. Behind Substitute you can't get statused except for Infiltrator Pokemons, but they are less. And for Dragapult, people generally keep Clear Body. Also there are enough priority healing moves to keep the substitute. Once behind Substitute this can be a pain to deal with.
So, overall I think this Pokemon can fit in any team quite nicely and provide healing support to save one move slot of teammates which may had been kept for healing move.