Never Tell A Child Maybe

I have learned that you never tell a child maybe. Maybe is a death sentence to tears and broken hearts. My Sisters husband has a tendency to tell my son he is going to do something with him then totally forgets he ever promised the boy anything. Of course him and my sister blame the child like he has a devious evil mind. The boy is 5 and while stupid the boy is not there are still some limits to his brain genius. Of course he is going to think you mean now. I am not sure what promise the man made he claims he did not promise he said "Maybe" about taking my son somewhere and then my son comes to me saying he is going out with his uncle like now. So I have to go upstairs ask what going on. This is constant occurrence though that is getting tiresome. The man is known to say fun day things to my son, but never plans on really doing it. He also always says I'm gonna do this, or I will bring you back that and then he forgets. My son did not forget and wonders why his uncle did not bring him back anything like he said he was going to. You do not really have to take child psychology 101 to know the kid is going to remember what you said and expect you to follow through with what you say. It seems children learn disappointment early in age. I know somethings can not be helped and I consider those healthy disappointments it's a part of life and healthy,but when the same person disappoints every time it's a bit heart breaking. You wonder do they care? So thus I learned never tell a child MAybe.