I pondered that question as well. Just guessing but I get the impression the family is poor. While the article does not go into details, I have heard of situations where Mexican parents don't marry because they can't afford the big party. (Pinging tax-chick who has more experience with the hispanic community.) Perhaps the Make a Wish foundation provided the fine clothes and food?
I’m sure the Make-a-Wish Foundation was not required for any of the sacraments, but simply funded the externals for the celebration. Perhaps there were also travel costs involved.
Often, Mexican couples have been married legally in Mexico, but have never had a church wedding. Sometimes it hasn’t been possible for them: the Church is spread thinly in the poor parts of Mexico, and there is a lot of coming and going in the lives of migrant families. Also, they do like to celebrate grandly. If an extended family lives in the same place, they all save up and contribute together for weddings, baptisms, and other celebrations.
I’m very pleased for all of them.