I would never shoot a sow with cubs even if she was dry and no longer nursing as it is impossible to tell that at bow range. If the cubs are with her then you got to treat them like they are nursing.
That being said I would shoot a "dry" Sow if really old or if it was an accident. Actually, my bear was just that...thought it was a boar...big head, wide body, perfect coat with no rubs or rippling on the sides, no cubs or other small bears with her.
That being said I think cubs that are in their 2nd spring will survive fine as that is when the mother would kick them out anyhow. The first Spring...I don't think would work.....other bears would be their biggest threat and wolves I would think.
Here is my sow that even the guide thought was a boar until we turned her over to drag over log. I am getting her tooth aged as he suspected her to be over 14 years...teeth worn and yellowed...large skull (almost 19") and 300# with no fat on her at all for a Spring Bear except small fat saucers on each haunch the size of my hand.
Sows with cubs are illegal most everywhere. Dry Sows without cubs in attendance are not in most places. Follow the laws and then make your choice. I had no intention of shooting a sow though legal if not accompanied by cubs in Saskatchewan. Sometimes mistakes happen...as I was convinced she was a big boar.