Lincoln Financial denied my STD claim after a C-section saying 6 weeks is "not medically necessary" - has anyone fought this and won

my wife had our second daughter march 14th via scheduled C-section. her OB filled out the disability paperwork for the standard 6 week recovery, which is what every doctor and hospital we have talked to has said is the norm for C-sections. her policy is through her employer (mid sized law firm) and is administered by Lincoln Financial. she had paid into this for 4 years and never made a claim before.

they approved the first 2 weeks then sent a letter saying weeks 3 through 6 are denied because "the medical documentation does not support disability beyond standard postpartum recovery and you are deemed able to perform sedentary work from home." she is a litigation paralegal. her job involves long days at a desk, but also frequent runs to court, lifting expandable files, and sitting through depositions which she absolutely cannot do at 3 weeks post C-section.

her OB has already written a clarification letter. her surgeon (the C-section was performed by an MFM due to a prior complication) has agreed to write one as well. but i am reading horror stories online about Lincoln Financial denying STD on procedural grounds and dragging it out until people give up. her HR is being polite but useless. we lost about 4 weeks of income and are looking at maybe an additional $2,800 we wont get back if we cant overturn this.

has anyone here actually won a postpartum STD appeal against Lincoln, Unum, or one of the big STD carriers? what was the magic combination of documentation that worked? is this something where we should just go ahead and hire an ERISA attorney, or can we get there ourselves with good doctor letters and an internal appeal?