How would you handle this situation? (invite or dont invite to bday dinner)?

Ok, my mom's bday is today but I planned to celebrate it tomorrow. My bro gave me some ideas on how we should celebrate and his ideas are great. I did everything he said and we were gonna split the tab 50/50. The problem came up today when he asked me not to invite someone to tomorrow's dinner whom I told him I was going to invite and even that person knows that its my mom's bday, loves my mom, and was planning to celebrate with her. I was planning the same thing, I initially planned that for dinner it would be my mom, my brother, my sister in law (cindy), my 2 close friends, and anyone my bro wants to bring. I believe everyone deserves to celebrate this special day with my mom but my brother thinks otherwise. I told him 2-3 days ago who was going to attend and he didnt say anything and he put me in charge. The problem is, he said tomorrow, cindy can only come to lunch with us not dinner. Dinner was the finale! Dinner is where we have cake, take awesome pictures and enjoy ourselves!