To think my DH needs to handle things differently

[vinoinveritas]

Every time my DS (mid teens) is badly behaved, gets in trouble at school etc, DH tries to talk to him about it but 99% of the time, ends up shouting and swearing at him. DS is frustrating and answers back but DH just cannot seem to keep a calm head when dealing with him. Advice?

Why don't you talk to him instead?

Shouting and swearing is I'm assuming because your DH is also frustrated and is venting at DS. Perhaps ask DH how he thinks shouting/swearing helps support your DS to make better choices! Would he, DH, like to be spoken to in that way if he was struggling?

I'm also guessing however that your DH is frustrated because of how your DS responds when being spoken to (talking back, disrespect maybe?) and maybe because DS doesn't seem to be make any changes as continues to be in trouble.

Assuming no SEN etc etc, would either be open to family therapy?

Set in place a consequence rather than a talking to.
No pocket money for a month, no screens for a month, no going to a special outing - something that will matter to him.
Insist that the school expects a writen apology and son getting community service time.
Both of you just calmly enact the consequences of bad behaviour.

Make sure son is not misbehaving due to lack of sleep, too much junk food, addiction to games, bullying, undiagnosed chronic condition or copying poor parental behaviour.

Would he read this? https://www.peacefulparenthappykids.com/read/handling-anger