From the time I was 6 until after I left home. The situation was a bit different because our house had a mother-in-law suite, so he had his own space, but we saw him basically every day. It was great for us kids, we had an awesome relationship with him. But I know it was hard at times for my Dad living with his father-in-law. Whether or not it will work for you depends on your relationship with your parents and your wife’s relationship with them.