My family gives me mixed signals on my fiancé

My fiance and I have been together for almost 7 years, engaged for 3 months. My family has pictures of him in our family home, welcome him to Christmas and other special occasions, and when my fiancé told my mother he would like to propose, she had started crying and hugged him saying she was waiting for it for so long and told him that he was always part of the family. My brother and his wife have been married for 1 year, dated for about 8. Even though I have seen that my family loves my fiancé, I feel like there is favoritism at play. I say this because my sister in law has been invited to our family trip to Hawaii (where the rest of my family lives) and they even offer to pay for her plane ticket, lodging, food, as well as activities. Yet, my fiancé is not invited. I asked my mother about it and she said she just thought he wouldn’t want to go. Yet, the whole family, including her, talk about this trip in front of him and he responds saying how exciting it would be and how he would love to meet my family there. It’s very disappointing because he already took the time out of work and they have approved it. He works in the military so taking the time off was a little difficult. He’s bought gifts for my family in Hawaii and so many clothes to wear because he is so excited. He said he would be more than happy to pay for his own tickets and etc, but he doesn’t want to intrude if my mother does not invite him. I feel as though she is being unfair. Everyone except my mother wants him to be there and has openly expressed that to me. Another reason I feel she is playing favorite is because we came back to our hometown where my mother lives for the holidays and we will be here for 2 months, then we must go back to our home. My sister in law and my brother had lived in her home for 3 years straight and only left about 5 months ago. Yet, my fiancé is not allowed to stay here for 2 months during his time off. He is living with a friend he knows here but it is rather uncomfortable. We are living a part because his friend simply does not have room for me. He barely has room for my fiancé as he is sleeping on the couch. I feel so bothered by this because when I talk to my mother about this she tells me that it is not her duty to house him. Yet, she more than willingly housed my sister in law. For 3 years.

Am I overreacting by thinking she is playing favorites? She gives me some sort of positive by showing her love for him but then she will do these things like not invite him or allow him to stay here and it’s not only hurting me, but my fiance as well.

Any tips would be greatly appreciated.