First being able to edit related records using web app builder is AWESOME!!Web AppBuilder for ArcGIS
Now for my question.
I set up in ArcGIS online a webmap that has a feature class and a single related table. Under the configure pop-up i checked show related records and under sort options i set up the sort based on a date field. Now when I open this map in Collector on the ipad it functions properly, showing the related records in descending order by date.