19mo old son was injured and needed stitches and staples in head and hand at a house we were looking to buy.?

We put a bid on a house that the seller (foreclosed house that bank owns) said was ready to move in. They had done a lot of work on it and said it was finished and is ready to move in. We went and looked at it and my wife opened up the windows that open up and down. The bottom of the window was near the floor so my 19mo son was able to pull himself up to the sill and lean forward. He placed his hand on the bottom track and head across the plane of the window opening. Well right at that moment a spring broke inside the window (keeping it up) and came down on his head and then on his hand, causing a deep gash in his head requiring staples and stitches in his hand. Just curious if we have a law suit and if people think we should sue. We are leaning toward not suing but should we? Thanks for your input.