Whether you accept one of Aubrey's brothers is a decision that only you can make. I don't think that guilt should play a part though. If it seems too soon, then I would say it possibly is too soon for you. Everyone will have different feelings about this and of course it will depend very much on the individual circumstances.
In this particular case, I myself would be concerned about the health of the other litter mates, but you will be in a better position to decide on this.
I think perhaps you should wait a little while. Think it all through by yourself. I am sure that the right way forward for you will become clear.
As others have said though, I do hope that at some time or other you decide to give a home to another rabbit and when that happens, please let us know.