Awkwardness on Christmas...?

So back story DS is 4 1/2 and DD1 is 2 1/.2 their bio father has been in and out of their lives since they were born missing most of their lives all together. DS knows that's his "dad," but doesn't call him dad/dy neither does DD and I'm not even sure she's really thinks that's her dad...after all she's two and probably seen him 4 or 5 times for a few hours... They call my husband dad/dy... He does everything for them, etc.
Well, their bio dad has decided that he wants to help and has decided to come up Christmas & Christmas Eve (no guaranteeing that he will actually show up, he's not dependable), but I just see this being an awkward situation since they call my husband daddy...

What would you do?

Not a dang thing! If he's not in the picture he can't be mad and if he gets mad he can leave!

I would tell him no. He cant come. Im sorry but you and DH are the ones doing smurf for them. Not him.

i wouldn't worry about it at all, he's not in the picture, he can't get made over not being called daddy.

We dont all get together for Christmas, but DS calls my husband dad and calls his bio dad Mr. Chris... DS is almost 5. I just told sperm donor to deal with it, thats how it is because he is never around.

Quoting JiLLiAN.:" i wouldn't worry about it at all, he's not in the picture, he can't get made over not being called daddy."

That's what my husband said...He said it's his own fault.

Quoting ♛ Rudeness.:" That's what my husband said...He said it's his own fault."

exactly. IMO "you made your bed, you lie in it."

Whatever! I wouldn't do anything. My neice calls another man, "Daddy" I don't blame her or her step-dad. He's taken care of her 1000x better than my brother ever has or will. She just turned 12 and he's been locked up at least 70% of her life. Even he has no qualms about her calling him Daddy. He thanked him for doing his job.