If he is charged with a DUI, it is a bit more complicated. If this is his second drug offense, it is a bit more complicated. If it is his first drug offense, Montana law presumes that his sentence should be a deferred sentence. I recommend he find a criminal attorney to help him.
The landlord can make claims on your deposit for past due rent and damages to the property or other monies owed under the contract. He has to make a claim on your deposit to that effect. If he does not follow proper procedure, you may have a claim against the landlord for return of your deposit. Once the landlord has another tenant sign the lease, you are relieved from any rent obligations.
I am sorry to hear of your loss. If your son was emancipated, you do not have any rights to his property (per se). If he had a will, then the will must be probated. If he did not, then all his property passes to his wife. If he had children, then they would be next in line. You should contact a probate attorney if you feel you are entitled to any of the property.
There is no "accused" yet until an arrest is made. Constitutional rights of discovery and due process will not become ripe for claim until the government has made an actual arrest. If an arrest is made, the defendant will have rights to discovery, which will include affidavits for search warrant, warrants, statements, etc. If this person believes he is being targeted for investigation, he should obtain an attorney immediately.
is there a written agreement? If so, the agreement tells you how much rent is unless you signed an addendum to raise the rent. If your lease is a verbal, month-to-month lease, they cannot raise rent until they terminate the month-to-month lease by giving you proper notice and then requiring a higher rent to enter into a new lease. The government aid agreement may also prevent the landlord from raising rent.
It is a misdemeanor offense, so by legal definition it is "minor". However, I would disclose it if the nature of the question is trying to reveal what criminal record you have. If you are found later to have not disclosed what they think you should have, it could have worse consequences than if you would be open about it at the beginning. You may want to talk with someone in the administration on a more personal level about your matter.
Do not talk about the facts of your case. Anything you say can be used against you. You need consult with an attorney, and if you do not have one, either ask the court for the public defender or hire one. This is too serious of a charge not to be represented.