The diocesan tribunals are comprised mostly of priests who haven't a practical clue what marriage is about, never mind raising children.  They live in a world where THEY alone make decisions and don't have a spouse that also has a say about decisions.

It should be up to the priests on the parish that have discussed with the individual/couple the situation and who know the UNIQUE situation of the individuals.  This is dealing with the people as individuals, not trying to homogenize everybody.