Need to prep bread pudding on Thurs for Sat dessert. Can I make custard two days ahead? Need to make bread pudding ahead

By custard, do you mean a sauce to garnish the bread pudding or (maybe) the egg-milk mixture to bake in the pudding?
Either will hold up about 3-4 days cooked in the fridge.
I would bake the pudding Thursday, hold in the fridge, serve Sunday at room temp or slightly warmed in oven.