Friends mom has als. friend got tested and shows positive for familial als. she is 50 with no symptoms. is there a chance she may not get als?

Possibility: There are several genes associated with familial ALS and the majority are autosomal dominant with adult onset. There is one gene that is autosomal recessive that can have adult onset. So it would really depend upon what gene was tested for but there is a probability she will develop ALS if it is an autosomal dominant gene. However, clinical variation exists and it is hard to say for absolute.