First off I like it that you try to change the situation and that apparently you have a good relationship to your cousin.
All said, my cousin is good to me. There is always mutual help.
It's a good starting point for you. I deal with people on a daily basis - yes, I live (just joking). I mean I train and coach people. So here are some ideas what you can do.
Changing other People
Sorry, I have to take that away from you. You can't change people. That has never worked. The other person has to decide for themselves. I've worked with people who resist and you don't stand a chance - even though you know what you're doing.
What you can do is change yourself and/or your behaviour. This will for sure affect all the people around you. Also it's waayyy easier, since you want to change.
- When have you noticed that changing you changed your cousin?
- What can you change now?
I think it's great that you see the good intent in his action. Whatever people do to people they like or love, it's coming from a good place. There's a Indian saying "You can only judge someone, if you walked in their shoes."
In your case: Maybe he wants to protect your mom from the all the bad things that happen because she can't change it anyway. He feels like it would hurt her somehow. Yeah a better option would be saying nothing. There's a chance he's trained by his social environment that this is the way to go.
Whatever the case. Unless you know the answer there's no reason to feel like you're feeling right now. These bad emotions are not helping you to solve this. Good emotions though will make you feel better until you have your answers.
What good intent could your cousin have to lie at this point? ;)
You're What You Say
That's a simple one: Language affects us on a subconscious level. So if you take with your mom how shitty the situation is - how does that both make you feel? Does that change the situation in any way?
What people love to do is talk about the issue with everyone else besides the other person who really is the involved party.
Would it make a difference to stop talking about it until you solved the issue?
Questions are Powerful
This one was a real eye opener to me. Asking the right questions makes a difference in the conversations you have.
Let me give you an example: Usually when you have a conversion it goes like this.
You: "Hi, how are you?"
Other: "Good. You?"
You: "That sound's great. I've seen him lately.."
Other: "Really. I have.."
Normally you don't think about what kind of questions you can ask rather than telling something of your own. Here's the point though: if you want to change a persons perspective you have let them decide for themselves. With questions you change the focus of a person and let them find their own solutions. Have you noticed that I'm not advising you rather than asking questions?
Some examples for good questions:
- Never ask the WHY Questions (goes to the past). The only thing you'll get, is a defensive justification.
- Open questions like: What are you trying to accomplish with the lying (please be fair at this point since you don't know his intention)? How does that help your relationship my mom?
Which one of these feel good to you? What other questions could you come up with to let him reflect?
Circular Questions (Advanced)
This takes some practice and is a good technique. What you basically do is ask the following:
Imagine you're my mom and have her feelings. How would it make you feel to be lied to? Would you want other people to lie to you?
For your cousin to change he has to decide for himself that he wants to change something. This only works if he feels how your mom feels about it. It's important that you yourself feel relaxed when you have this conversation. Emotions are infectious. If you're angry, he'll be angry soon enough.
What kind of circular questions (change of perspective) can you ask him that you think will work?
I hope this helps somehow. Feel free to ask any questions :)