Can children lay claim to any share of a house belongin to their father and stepmother.

the answer to this is going to depend on several things.  first, how were both names on the deed?  If both names were on the deed and joint tenants with right of survivorship - then the surviving person gets the whole property. Second - did the husband have a will?  What does the will state? If the husband did not have a will, who is the administrator of the estate?  what other assets are in the estate?  All of these facts need to be discovered before an answer about the division of estate assets can be determined.