Kinda like Linda Tripp coming out because they BOTH would have wound up in Marcy Park.
Remember, even our former perverted President had to give a DNA sample.
Back to subject...Martino would KNOW if Danny was a druggie...Uh...And I don't think a lot of druggies would contact a PI because they were worried about Mom and in particular...probably KE and Howard (which may be the case).
I found it particularly questionable that Danny would tell KE that he had a tummy ache and was taking a certain anti-depressant. For all we know, she gave him big, white tablets for his tummy ache.
Maybe Danny was playing KE - letting her "think" he was a drug adict so he could find out who exactly was supplying his mom, IMO