Alan Thicke's Widow, Tanya, Wants His Sons to Hand Over Her Inheritance Already

Alan Thicke's widow says his sons are treating her unfairly and believes they might be recklessly spending his money while holding out on her inheritance ... according to new legal docs.

Tanya Thicke claims Alan's sons -- Robin and Brennan, who are co-trustees of their late father's estate -- are not only keeping her in the dark about how they are managing his trust ... but are ganging up on her and possibly robbing her from what she's owed.

According to the docs ... the sons raised hell over Tanya arranging a burial site monument for Alan -- which she claims she had every right to do -- and retaliated by refusing to reimburse her for it. At the same time, she claims they reimbursed Robin $105,000 for a huge memorial bash the night before Alan's burial ... which she was not on board with.

Tanya also believes she's being unfairly charged by the sons for expenses and taxes that should not fall on her.

Tanya's lawyer, Adam Streisand, tells us ... “The fact that Tanya still hasn’t received her inheritance is unconscionable," and adds if they don't start being more open with what they're up to ... Tanya will get the court to force them.

As we reported ... Tanya scored a legal win over the boys last September when a judge tossed their petition to block her from challenging her prenup with Alan, which she never did.

We've reached out to Robin and Brennan ... so far, no word back.