MIL got main present for DS

[FarFarAwayLand137]

Back in November my MIL asked what DS5 might want for Christmas and I mentioned a Lego train set he had seen in the shops so she got that as a joint present with FIL and BIL.
Since then DS has visited Santa and asked for this and told everyone that Santa will get him a Lego train set. Now I'm worried that on Christmas morning he will be disappointed that it isn't under the tree and Santa hasn't got him the one thing he asked for.
MIL will visit later in the day and obviously bring his present but what do I say if he asks why Santa hasn't got it for him?

Why doesn’t MIL just drop the present to you before (with her name on tag) and he opens it in the morning? Film him opening it if she really needs to see his reaction.

My parents always drop presents off the night before for children to open in the morning , even though they will see them later. They buy for the children not so they can see the children’s reactions or take the glory of being the one who bought it

NRTFT

My in-laws have regularly got gifts of the Christmas list, they use to bring them over telling my DCs Santa left them at their house for my DCs. Just make sure your DS knows there is more to come.

Say maybe Santa couldn't fit it in his sleigh and that's perhaps he could get it for his birthday instead.

Don't do what others have said about MIL having bought it. That ruins the very lovely surprise.