IMHO, MPL training ONLY if full financial responsibility assumed by airline.
If your son fails along the way, in any way, his license is nontransferable nor will it qualify him for a non-airline flying job. That's a whole lot of other opportunity out the window.
There's also a lot of stuff written about Qatar and their reporting staff culture, as well as life in Doha. I suggest you have a good read before committing.
Good luck!