The written agreement will usually control over any inconsistent oral agreements.
You have several issues to contend with in this eviction and they are going to be fact sensitive so I strongly suggest you retain an attorney to assist you to fight the eviction.
However, in light of the family issues involved as well as the impact which an eviction can have on your credit and ability to lease other places, you may want to seriously consider trying to resolve this by an agreement to leave after a reasonable time to relocate. Discussion of that with an attorney would be a good idea under the circumstances.
Good luck. Note: This response is: a) limited in scope to questions involving Texas law for a Texas resident; b) is intended only as a general information discussion of an issue raised in the question presented; c) does not constitute legal advice as all relevant facts are not known nor analyzed; and d) does not create an attorney-client relationship.
As the saying goes, an oral contract is only worth the paper it is written on. You and the landlord are bound by the terms of the written lease. You need an attorney, to claim damages for you being "constructively evicted" by the actions of the landlord's son. You should be claiming the costs of moving and the difference between the two rents, for the remainder of this lease.
You have asked 2 different questions. As to the lease -- it depends. If you want to fight any language in the written document, then you will need to challenge it in court and allege fraudulent inducement. As to the eviction -- you need a lawyer to help you fight it. It sounds like the eviction is not based on any terms in the written lease. And you should consider filing a third party claim against the 42 year old son on behalf of your 13 year old son, which will position you better to work this out.