Alan Thicke's widow, Tanya Callau, just got an assist from the judge in her legal battle with his 2 sons over her prenup and the future of Alan's estate.

The judge threw out a petition filed by Robin Thicke and his brother, Brennan, Thursday to block Tanya from challenging the prenup she signed with their dad. The judge decided the brothers' concern was misplaced, because there was no evidence Callau had any intention of mounting a challenge.

This is exactly what Tanya claimed back in July, as reported by TMZ, when she accused the boys of filing the legal docs simply to trash her in the media and make her look like a greedy widow.

It's not a complete victory for Callau, though -- the judge left the door open for Robin and Brennan to file a new petition on the matter, but he would "need more specifics." Their lawyer suggests they will, because there are other disputed issues besides the prenup ... like exactly how to divvy up Alan's property.

Tanya's insisted she just wants what's rightfully hers -- a cut of Alan's ranch, a right to live there and chunk of his other assets.