I would not provide it. If its not something we eat as a family then its not something I provide. There is more than just buying the meat to this.
You have use seperate dishes/utensils/storage containers as well as seperate cutting board/counter space and pots and no other meat can touch this meat or it is no longer consider Halal.
I had a family who wanted me to provide care that was kosher. I had to turn them down. We lOVE Bacon around here and PULLED PORK is a family favorite, as well we eat meat and cheese often at the same time ( hello cheeseburgers and meatball subs with cheese) I have no intention of giving those up or changing my kitchen around to statisfy this child's religious needs, and the parents did not want her only eating vegeterian while here. Even if they had agreed to vegeterian only I still would had to keep the meat far away from any food she would have eaten.. Too much of a headache
If you do want to provide care, I would only serve vegeterian meals to this child then you do not have to worry about keeping Halal, but depending on how strict the parents are with this that may not work either.. They may only want Halal meat in the home.