i dont know if you can help the situation get better, but i think this is all because ur inlaws (probably ur MIL) does not show much effort to stay in touch which actually a lil weird (whats d frequency??)… That might change when ur get married and have more ‘power’ to tell ur MIL to keep in touch, if thats what you want. But on the other hand the distance is fine too. This is what ticks ur mom off so much.
I think ur inlaws should try keeping in touch and u said ur mom didnt want to go to their home?? but she did go to ur sisters inlaws?? Its about how much theyre giving… it comes from both sides, u cant help it i guess.
But still ur mom shouldnt act like this, its not mature.
Theres not much more to do ro say i think..