Husband offers niece her wife's piano without first consulting with her if she wants to give it up, now sister-in-law wants her to pay the $300 fee for the movers: '[Wife said] that if [SIL] wants it for her daughter it’s $1,400, and take the $300'

If your husband is gifting your things to his family without even consulting with you first, maybe he isn´t the best husband. Although he may be a good uncle.

If I were home one day, relaxing and chilling, and I got knocked on the door by some movers who had an order to take my piano, which was gifted by my mother, without me ever knowing it was going to happen. I will simply say 'no' and close the door. This story is very particular, first of all because it is a big family drama whose only cause is the entitlement of the husband. The first thing that went wrong is that this husband assumes that something that is his wife's can be gifted without ever asking her. He didn't stop for a minute to think whether it was fine with her to give it away or if she wanted to keep it; he just assumed what he wanted as if the piano were his. Secondly, he made the arrangements for the movers to come pick it up, making her sister spend $300 to not move a piano. This is entirely his fault, as he should have at least said he hasn´t yet talked to his wife about it, so to wait a week before sending in the movers. And lastly, he never said sorry. This whole situation is entirely his fault; he promised his niece a piano that she isn´t going to get because he didn´t even bother to confirm if it was available to give out in the first place. 

This is my perspective of the story, but I cannot see any way in which the husband isn't the one to blame for everything. I'm assuming the sister-in-law and the niece weren't notified before that all this would be done without the owner of the piano knowing. So if I were this sister-in-law, I would be pretty mad that I spent that much money on movers only to be turned away when they were already there. But after finding out whose fault that was, I would be expecting my brother to pay me back for all that. He is the one who should have made sure in the first place that the piano was available to give out. Now I also imagine that the niece is pretty sad about all this. Imagine that someone tells you they can give you their piano for free, only for that not to be true. It's hard. But the greatest anger should, of course, come from the wife who now cannot fully trust her husband as to what has happened. Let's hope this husband does something to redeem himself after this horrible misunderstanding that he single-handedly created. Let's hope he at least learns to ask before making decisions for others without consulting with them first. His behavior was wrong; the minimum thing he can do about it is ask for forgiveness, but he shouldn't be surprised if he is not forgiven.