The priority date for F2B from the Philippines has been moving slowly.
It has moved 7 days in the last month.

My brother's priority date is November 1998.
At this time, the US is only processing March 1997.

His priority date is only 20 months away according to the priority date which is moving slowly.

If this date moves 7 days for every month that passes.

Its going to take my brother a little more than seven years until his priority date comes.

20 months = 600 days
Priority Date moves 7 days for every month that passes.
600/7 = 85.7 months
85.7/12 months = 7.14 years!

Is my calculation correct more or less?

Thank you.

It doesn't work like that.

It depends on how many F2b petitions from the Philippines are ahead of his. There's no way to determine that number. There is also a fixed number of F2b visas per year. The Visa Center starts issuing them when US law makes them available (I believe it's the start of the fiscal year - Oct. 1) until they run out. So, by the time that the April comes around there is a slow down in the number of available visas. They could also be gone and the visas that aren't used are reissued to someone else (i.e. original visa issued to someone who got married and is no longer eligible for a F2b visa). The priority dates for all categories should start jumping faster than they are now in Oct.

Bottom line: your brother will not be waiting for another seven years.

Your brother should be careful that he is not recategorized. He should stay unmarried and petitioning parent should wait until he comes over to the US to become a US citizen.

Philippines:
F1 (unmarried children of US citizens): 15Mar93
F2b (unmarried children 21 or older of LPR): 01Mar97
F3 (married children of US citizens): 01April91

Married children of LPR cannot immigrate.