From my googling, beer tends to contain around 16mg/L of methanol. While for brandy, typical methanol content is around 1000mg/L (give or take a factor of 3, depending) The distillation that brandy goes through attempts to concentrate ethanol and remove methanol, yet we end up with an 8x worse methanol-to-ethanol ratio.
You state, "The distillation that brandy goes through attempts to concentrate ethanol and remove methanol." AFAIK, the intent of distillation is to concentrate ethanol only.
However, the statistics you quote are misleading for a few reasons.
Brandy is not generally distilled beer, but rather from wine. Your comparing apples and oranges... well, beer and brandy. Would it not be better to compare alcohols in wines and brandies? Also, pick the same type of wine and brandy, e.g., plum wine vs. slivovitz.
Water is removed by distillation, leaving a higher percentage of ethanol, so the ratios you quote are misleading: comparing beer, about 4%-6% ethanol with brandy, about 40%-60% ethanol, one should measure concentration based on the amount of alcohol in the beverage, rather than on the total volume. That would make the beer about 0.4 g/L methanol:ethanol, and the brandy about 2 g/L, based on the statistics you gave for the amount of methanol. What is the source of those statistics?