It is the last service you can do for someone who has passed away.
As executor, you can appoint solicitors to do all the leg work. You can pick a firm who provide good service and if they don't do a good job can change them relatively easily.
They will report to you so that you have a reasonable idea of how long things are taking. While you have responsibility, it doesn't stretch beyond what the solicitors report to you.
All their costs will be met out of the estate. You can claim reasonable expenses, eg cost of postage if you send them documents
If the firm of solicitors are appointed in the will, the process of getting them ousted if they do a really bad job, taking forever, is much, much more complicated and costly. The will is likely to have been written a long time ahead so that it is difficult to know what will have happened to the firm in that time.
No one can force you to be executor. Even if you are appointed in the will you can renounce. It is however a big service you can render a friend, to oversee the distribution of their estate according to their wishes.
The one thing I would ask, in order to agree, is that they make it as easy as possible for you, including:-
Provide you with a copy of the will for your info and talk you through it, rather than tell you what it contains and then have you possibly be surprised when you do finally get it.
Make sure their affairs are in good order, so as a minimum one folder with all the information you need, including their accounts with numbers and identifiers, mortgages, loans, investments so you don't have to search this information out for your self.
Provide a letter (alongside the will) with expression of wishes, to cover any ideas they would like such type of funeral, order of service, flowers or not, catering for after the funeral etc, particular charity to benefit from clearing out the house, so it be is clear what they wanted. There are lots of decisions to be made, which are much easier to do, if you have some guidance. These are things that would not normally made it into the will but are so helpful to know in the emotionally charged time after a death.
Ensure her children also know the provisions of the will, expressions of interest and your role.
With all that in place and kept up to date, your actual work as executor is reduced to a minimum while still rendering that last service.