Parents’ birthdays are supposed to be happy occasions, but it’s not so happy when siblings squabble over who pays for what.

This man had treated the family to dinner on their mom’s birthday.

Then, his sister then threw a surprise party for their mom.

Now, she also wants him to help pay for the party. Should he?

Read the full story below to find out more.

AITA for not wanting to pay for a surprise birthday party I didn’t plan?

My mom’s birthday was recently.

On her actual birthday, we celebrated at a restaurant.

I paid for myself, my wife, my two kids, and my mom and dad’s meals.

I also bought my mom a gift she’s been wanting ($100+).

This man’s sister threw a surprise party for their mom.

A couple of days later, my sister threw a surprise party for her at our grandparents’ house.

I didn’t plan it—I just showed up.

I also bought some of the drinks for the party.

His sister asked to split the cost, but he plans to refuse.

Now my sister is sending me a Cash App request to “split the cost” of the party.

I feel like I’ve already contributed a lot and didn’t agree to throw this party.

AITA if I don’t send her money?

Should he help pay for the party, or has he already done enough?

Let’s check out the comments of other people on Reddit.

This user shares their personal thoughts.

This person offers some honest advice.

Here’s a valid point from this user.

This person gives their honest opinion.

And finally, people are siding with him.

Splitting costs should be agreed upon prior to the event.

If you enjoyed this story, check out this post about a daughter who invited herself to her parents’ 40th anniversary vacation for all the wrong reasons.