How do I respond to a guilt trip from my parents?
Name the feeling, then restate your decision with something you can offer: "I know you're disappointed. We're not coming this weekend but we can do the following one." Do not defend the decision at length. The more you justify it, the more it sounds open to negotiation.
Should I reply to family by text or call them?
Text is good for a short, calm holding reply. Anything with real feelings on both sides usually goes better as a call or in person, where tone does not get lost. A text that says you would like to talk is often the right first step.
How do I reply to a passive-aggressive message from my mother-in-law?
Answer the literal message and ignore the dig. Respond to what she asked or said, warmly and briefly. Leave the subtext alone. If it becomes a pattern, it is usually better raised by your partner than by you over text. Screenshots and long replies tend to become the next argument.
What if they keep bringing it up?
Use the same short line each time rather than a new argument: "I've made my decision and I'd rather not go over it again." Consistency is what eventually ends it. A different reason every time keeps it alive. If it is starting to affect how you feel about seeing them, say that once, calmly, ideally in person.