When you got the plant, did you repot it? If not, and you think mommy plant is dying, I would check the condition of the roots. This plant is quite drought tolerant with very fat roots, that is why you were advised about overwatering. Since it is indoors, and can take low light, the drying time after watering gets longer. So you really have to adjust and hold back watering. I will just snip off all the dried out leaves of mommy plant, and wait for it to recover. It should bounce back. But do check the condition of the roots, just to see how it is. It may also be too root bound already, so you may have to consider repotting. Typically I would do the repot in Spring, but you grow it indoors anyways, so your growing conditions will be more controllable.
No, those little babies does not drain energy on the plant as far as I know, I just keep mine growing till I snip them off and replant to balance the overall look of the plant. You may want to do that, replant some of the babies with good roots so you have a back-up in case the mother plant is indeed dying.
This is how the roots of a very mature spider plant looks like: