DH mum has died, she left a will that was typed and witnessed by her two lifelong friends but it wasn't done by a solicitor. In it she left half to my DH and half to a lady who looked after her for the last ten years. She had a poor relationship with her daughter DH sister, she hadn't seen her for over a year when she died and she left her a painting but nothing else. No probate was required and the small amount of money and belongings have been distributed as per the will. The sister is now causing merry hell and intimating she is going to contest it. Is this possible as the estate has been administered?