Upvote:1
The problem is with Bangladesh govt and Biman. They invented their own rules that unless you have a UAE visa, you will not be allowed to board the flight from Dhaka.
Hence, I ended up cancelling all flights.
Upvote:2
Just about anyone can transit (including a change of terminals) at Dubai without going through immigration. I was able to do so when all entry into the UAE for foreigners was suspended earlier in the covid-19 pandemic and I needed to get home. Though of course the situation is dynamic and subject to change, I'd be surprised if Dubai continued operating flights but not allowing people to transfer among them.
The main difficulty might be convincing Biman to let your father onto the initial flight without evidence that he can enter the UAE upon arrival, though hopefully it will be sufficient to show the ticket for onward travel. It might be worth contacting the airline to see if they are okay with this.
As you mention, Dubai is usually one of the few airports in the world where there is a service to transfer your checked bags for you without clearing immigration when checking the bags through to the final destination is not an option, but it appears from your research that this service is unavailable to you for some reason I don't understand. It, again, might be worth contacting Biman to see if they have a way to check the bags through to London. Failing that, your father may have to travel with carry-on luggage only.