If your house is relatively large and there are spare rooms to live in, then if your lover's brother and sister-in-law come to visit you from afar in your city, they can choose to live in your home. You and your lover can also get together with TA's brother and sister-in-law, have a good chat and get to know each other better. After all, we are all young people. When we are together, there will always be many topics.
If the house you live in belongs to a small room and there is no spare room, it is obviously inappropriate for TA's brother and sister to come and squeeze in with you. You should ask your lover to explain the situation to TA's brother-in-law and help him book a hotel.
These are my suggestions for reference only. I hope my answer can help you and make you satisfied.