My thoughts of the search and/or drug dog were if he was staying. It would be rather foolish to not search if he is going to stay in her home, in my opinion. She has 2 other kids there and NOT doing all she could to keep drugs out is just dangerous and while no one would say much about her 17yo, at least here the 14yo could attract CPS attention if anyone mentioned difficult child moving home with his drugs to a teacher, therapist, psychiatrist or other doctor.
Laws and customs are different in different areas, but I know parents in our town who have had to do searches etc... to prove to CPS that they were doing all they could to keep a drug abusing adult child from harming their teen children. These teens were NOT of the age to think it was candy, etc... the way a toddler would. It was still a real problem with CPS where one family finally was given the choice of keeping the minor child in the home (15yo) or the adult addicted child and it was CPS making them choose. Of course the addicted child thought they should let the minor leave, and that was a huge shock and finally opened their eyes to the true extent of the disease of addiction.
I know to many of you I seem to go overboard. Part of it is having an older bro who would tell me that I was a "prude" because I never wanted to try drugs and quite often he told me he was going to put drugs in my food, drink, even my mouthwash (why I never used it as a teen - not for any reason) and toiletry products. I was also told he was going to come in while I was asleep and tie me down and either force drugs down my throat or inject them into me - so I could quit being "better" than him. I NEVER thought that - I admired a LOT of the things he accomplished that I knew I could never do (like going to Antarctica). I just thought that he could be so much cooler with-o drugs/alcohol.
I also suggest things because I know what the police and CPS do HERE. We do NOT have CPS that will ignore everything. They are BUSY here largely because they will NOT ignore problems just because no one saw a parent hit a child. Our judges support them and they can do a LOT that I guess they cannot/will not in other areas. Regardless, I do understand that the things I suggest are not feasible for every situation. I also think with minor kids in the house, they must be kept safe.
Sig, I think sending a check to the landlord is find. IF you and H can become resolved and get the pcs to not let him in next time he comes around. Or let him in but with the understanding that a X time he has to go to his residence because your residence is not his until he has gotten help and is drug free and can prove it. Your easy child's NEED you to do that, hard as it will be and even if they say they don't think it is needed.
I really hope and pray that he is soon able to accept the help he needs - for whatever reason. I also hope that you and H can get your life back to an even keel again. I totally understand and support your actions, even if I have other suggestions. I know very well that not every suggestions is right for every family at every or any point in time.