I'm feeling very uneasy... your welcome to read and give a thought..?

The person i rent my house from is selling the property my house and his house are on, two houses one piece of property all owned by him my former brother in law (ex is my sister) i pay 300$ a month to him to pay for the cost it was to put the septic in, also i pay a portion of the property tax and irrigation. but we don't have a fomal agreement, his my word and his word between us. we've been searching for another place to live somewhere big enough for our family. and he's looking too sell his but for more then i can afford, so today he tells me someone is coming on sunday to view the property, and asked me not to be there when they where viewing my home, my son is 6mo and fairly ill as is my daughter. i own a huge dog (mastiff/dane mix) i pointed out it would be bad for me to be gone and people show up to see the house, because my dog wouldn't tolerate unknow people without us there. and he asked to take the kids and dog and go to the local park.. there is more