Multiple eggs in a cell usually indicates laying workers.
Do you know how long there hasn't been a queen or any signs of worker brood? Are the bees allowing brood to develop or do the multiple eggs get removed before they develop? (A good sign that they are drone as a weak colony in September will not want to produce drones).
Is there one or more open queencells present (might look old by now?).
Laying workers usually lay eggs in splodges in various places on the combs rather than in a central sphere in the middle of the brood nest as you would expect of a queen.
If laying workers, there is no point in trying to recusitate the colony even in summer by the addition of brood or a queen and at this time of year it will be even more fruitless.
To combine it directly with another colony can be dangerous to the queen in the good colony. However if your colony does have laying workers and it is near another one, then if you move the LW colony to the other side of the good one, the flying bees will return to their old site and not finding a hive, will find the queenright one and boost it's numbers.
Depending on the weather, you might then shake out the LW colony a few metres away and more flyers will find a queenright colony. (Do a final check for a queen first, perhaps). Some bees won't make it of course.
Provided there is no concern about disease, the good comb can be kept.
May your bees read the same books as you do.
