Blather44 here is a link that I hope will help, www.breederscorner.com/marewontfeed.shtml also I just wanted to say I'm sorry I haven't been around much. In case you need help right away, contact me at firstname.lastname@example.org, because this is my work addy and I will see it right away. Hope everything works out!
Just in case the mother still doesn`t want to nurse, see if someone around you or a breeding farm has a broodmare that has weaned but still has a full bag or start with goats milk in bottles. Hope the colt gets better