[Discussion] is this animal abuse?

My dad and his gf have 2 cats. One is a stray that was there when my dad bought the house. The other is my dad's gf's daughters cat who has moved away. The cats are outside during the day. I dont agree with it but we live in a rural area and a LOT of people do it. I noticed they have a bowl with water inside but not outside so the cats can't get water if they need it when they are outside. Both my dad and his gf are retired so they are there to let the cats in when they want in I think but other then that they don't have water outside. My guess is they are getting it elsewhere since they look to be healthy and they are obviously alive. Is this abuse? My guess is its at least neglect.