When my son was born, the inlaws all came to Pattaya from Nong Khai. Our newborn was bundled as was usual, and I had him on one of the balconies.
Paw insisted on covering our covered baby with a huge blanket. I removed it. He put it back.
I told my wife to tell her father, that I am the father and it's my house and my rules. He did it again. I told her to tell him that if he contradicts me one more time, he will find himself on the other side of the fence, and it will be me who throws him over.
No more problems.
#4 - Grow a pair.