Colostrum - will there be any left for DS2?

I'm currently breastfeeding my 18 month old son and he doesn't look like easing off any time soon, if anything he's demanding more boob and I'm due with my second in 5 weeks. Up until now I haven't been concerned but my DH has asked a couple of times what will be left for DS2 in those first few days when he needs colostrum and although I reassure him that it all works out, that this happens all the time, I can't find much information on the topic..

So does anyone know for sure, is colostrum effected by breastfeeding right up until the birth (I have also reassured my husband DS1 will have at least a few hours off the boob while I'm in labour!)?

Your body will produce colostrum for the newborn! I am currently feeding a demanding 26 month old and an 8 month old.

Your body changes the composition of milk with change in hormones post birth!