6 mos ago i married a man with 4 grown children. he is making a new will. what is fair with 600,000 estate?

all of the children, 35 and older, and myself are healthy and able. my husband is 62 and i am 50. two of the children are his deceased wife's from a previous marriage. They were 2 and 4 when couple met. my husband raised them as his own but did not adopt them. I would like to know what the law says is fair and what anyone else may think is fair. Current lawyer thinks each child should get 100,000 dollars. is that fair?