Help being less avoidant?

so a friend of mine is really struggling with changing. i won’t go into detail but he wants to be less avoidant and able to form secure relationships with people. what advice would you give him?
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edit: so there’s been so great reply’s, but here’s a little more about him. he can talk to people but eventually he’ll shut down and become mean basically self sabotaging everything. he hates anyone getting too close and he uses the fact that people say he’s like his dad to justify the way he acts.
Help being less avoidant?
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