How much independence is too much for a 4 year old?

My ex and I have a 4 year old son. We got into a pretty bad disagreement the other day and couldn't reach any kind of compromise.It started because my ex told me that our son has been peeing in his living room on the floor or wherever, which shocked me because he's been potty trained for over a year and I've never had any problems with him. As we talked, it came out that my ex leaves our son alone in the house for 10-15 minutes at a time to go smoke and sit to "relax". He also takes naps during the day and leaves our son alone to play by himself. He has left our son sleeping on the 3rd floor of his house alone while my ex was asleep in the basement living room..all of this shocked me, and I immediatly kind of laid into him for leaving a 4 year old alone so much. He argued that he's "a big boy" not "a baby" and "shouldn't need constant supervision".It escalated from there, him calling me a helicopter parent because the longest I leave our son alone is to go grab a drink or snack. He can play in another room, but I'm always within ear shot. I'm not asleep, or outside, or 3 floors away.. so if he yells or falls, I hear it.He feels our FOUR year old isn't "independent enough" and should be able to do a lot more for himself than he does. What he meant by this, idk.. because our son already dresses himself, can pour his own drinks, use phones and tvs, clean up his own messes... I feel he's doing just fine for a FOUR year old.What's your opinion on this? via /r/Parenting http://ift.tt/2wxFXS0