Visa Visa for parents to Accompany my wife who is pregnant

There are two important things in such cases.

1- Visit visa (online) is issued based on many different factors. The profession on the iqama, the applicant's company file situation in Jawazat, the current volume of applications,...etc etc. The difficult part is that they don't tell you why they have rejected some visas. You may try applying for a visa yourself rather than your brother.

2- I've heard it many times that if you go to Isteqdam and show them some evidence papers, they may issue a visa right away. I haven't known anyone for whom this have actually  worked. The only paper you'd need is your wife's medical report. You may visit the hospital reports office and ask them for such a report preferably in Arabic.

I had the case similar to yours; applied for parents' visa (in Riyadh); got it in 3 days; processed in home country; they are here nowadays ahead of expectation time. Nevertheless, I know because of the volume of applications and some technical issues, visas are being delayed by all the MoFA office across the Kingdom.

Hope this helps; All the best!