Filing timeline responsibilities of attorney

After a messy, years long dispute between my husband(+his sister)against their stepmother, they completed mediation, and agreed upon a lump sum being dispersed to them from the estate. It has been a year, and her attorney hasn’t filed the paperwork so that they can move forward and get the $. According to her lawyer, in reference to CC 1657, he says that there’s no legal obligation for him to file in any specific amount of time, given the fact that she had to come up with so much $, so long as they “move things forward in good faith and in a reasonable amount of time” She now owns two homes, worth over a million a piece, in Berkeley. Obviously reverse mortgage, or sale of a house is possible and could be done very quickly. Can her attorney just keep us in limbo like this? This takes place in Alameda county, CA, city of Berkeley.