Should I bring it up to him ? Is it worth being upset ?

My partner and I have been together 4 years with a 1 year old. He has bipolar and went off medication. A couple weeks ago, we got into a major argument because he had a manic episode and I found out he was neglecting to pay bills because he was spending on extravagant clothes. Since then, we have made up and he promised to go back on meds & to stop being irresponsible with money. Well today, he decided to go to the gas station and, when I asked, wouldn’t tell me what he was going for. He randomly comes with back with a power ball ticket, ONLY a powerball ticket, something he has NEVER bought in the whole time I’ve known him, and showed it to me and made it a point (without me even asking!) to say that it was “only $5” multiple times. I thought it was really weird but let it go. Well he was letting me use his phone to look up where to take bottle returns and his sister was texting him from their family group chat. I tried to swipe it up so I could keep searching but accidentally opened the chat. I read their conversation and he’s telling his family that he spent $10, not $5. And mentioned to them twice that it was $10, not $5 like he told me. I’m really confused on why he would lie? Unless it was more than what he’s telling all of us? And why would he randomly start doing this?