My mum had been inactive for a couple of years when she resigned, the bishop did not even contact her to check she wanted to resign, so perhaps it may go that way too for your mum.
The procedure is that the bishop needs to check you do wish to resign and are not being coerced. The bishop of my ward delayed and delayed to do this so I had to go to the SP through a friend in the end, and the SP told the bishop to do his job.
So you see procedures are not there to make it difficult, in fact they are there within the structure to help you to leave.
Some men, like all of us, can be awkward and it may take longer when so. The stated time by membership records is 6 weeks, but like I said, we have regular recent reports of much faster times than this.
If you want to move outside of normal procedure it will take longer.
If the bishop wants to come, let him. It is in your interest, if you do want to leave.