Sounds like your boy is acting out because of the disturbance in his life. Children do not have the complex emotional standards as we adults do, so in times of stress and disturbance in their lives they tend to act out in specific ways. Pooping in his pants gets him attention, and even though it's negative attention, it's still attention which he is craving. He does not necessarily understand what he is doing is wrong, he does not have the mental facilities for that yet (being only three). Do what I did, make him clean himself up. It's a nasty job and he will soon realize this. Spend more time with him during this transitional period, and expect to need to potty train all over again. Scold him when he messes his pants, and make him clean himself up (assisting him as little as possible) and give lavish praise and attention when he uses the toilet correctly again.
at 6:34 PM on May. 3, 2011