Dr. Ben Carson Ripped for $2 Tubman Crack ... HE Needs Brain Surgery

4/20/2016 3:23 PM PDT

Dr. Ben Carson Ripped for $2 Harriet Tubman Crack ... HE Needs Brain Surgery

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Dr. Ben Carson took a huge shot at Harriet Tubman when asked about her bumping Andrew Jackson off the $20 bill -- and now he's getting blasted by another historic woman's family.

If you missed it ... the ex-prez hopeful went on FOX Business channel and not only sang the praises of our 7th president, but suggested Tubman be relegated to the $2 bill.

Rosa Parks was also in the running to get a new spot on U.S. currency, and her niece, Sheila Keys, tells TMZ ... Carson "needs surgery on his brain" and clearly puts zero historical value on Tubman's contributions to America.

As for Rosa getting passed up -- Keys says her aunt "was not a diva and being on a dollar bill does not represent what she's about."