Police documents, published by the LA Times newspaper, said Mrs Palin called the police at about 20:40 on Saturday night (06:40 GMT on Sunday) to say her son was on "some type of medication" and was allegedly "freaking out".
The affidavit by a responding officer said they found the former Alaskan governor "visibly upset" at the property.
Police say that when they arrived they had a stand-off with Mr Palin in which he moved around the house and at one stage went out onto the garage roof. They say he demanded police put their weapons on the ground and allegedly called them "peasants".
Police say the struggle between the two men happened after Mr Palin said he was coming to the property to retrieve a vehicle, and threatened to beat his father.
Todd Palin, Mrs Palin's husband, told police he armed himself with a pistol when his son arrived, but was disarmed and was left bloodied.