Advice? Can't trust my dad whatsoever.

Jill • 18 | high school senior | 6 months in a relationship
So my dad is a recovering alcoholic...or at least I thought he was. His room is always locked and I've been wondering why...well he's not home and left the key on the bathroom counter, so I grabbed it and went in his room...there were cigarettes everywhere (I knew he smoked)...and a shit ton of boxes of Budweiser beer, most of them empty. I was suspicious yesterday when one of those empty boxes was IN MY ROOM. I asked him about it and he said that it must have gotten kicked in there while be was cleaning. I believed him. My family has been asking me how he's doing and if he's drinking anymore and I've been telling them that he's sober...he's been lying to my almost 13 year old brother and I. I wanna tell someone but I don't want anyone to know that I was in his room. Idk where to turn, I thought he was doing ok...I can't trust him anymore