Can he get in trouble for harrassment?

It depends on the laws in your state. Communicating a threat by way of electronic device is an offense in most states, but would they consider the phrase "I hope you finally kill yourself" a threat? Probably not. If he sends more than one impolite, explicit text AFTER you have informed him that you don't appreciate it, then yes. Otherwise, your local laws will vary on what is necessary for it to be considered harassment.

Good luck, and stop dating immature douchebags.

If there was only one nasty communication, he probably won't get into trouble as that isn't harassment. For it to be harassment, he needs to repeatedly contact you after he is made aware that you want no further contact with him.

This is what I recommend. Send him a registered letter (receipt requested so you have proof) telling him that you want no further contact from him at all (including in person, by telephone, by email, by instant message, or text message). And if he continues to contact you after receiving this letter, you will ask the police for a restraining order on the grounds of his harassment of you. And then change your phone number and/or block him.

One last thing. Save this communication and save all future communications you may receive from him. If and when it comes time for a restraining order, you will have the evidence of harassment you need to get the order. Good luck!

Change your phone number and your problem is solved. This would not constitute criminal harassment, so no he won't get in legal trouble for it.

There's a much longer answer, but here's the short answer: NO.

Stop wasting your time worrying about getting him in legal trouble, block his number, get on with your life, and stop worrying about stupid 14 year old bulls**t.