I'm sorry for your loss. My father passed when I was 17, oddly enough, cigs were his demise, too. Fucking awful way to go. He was first diagnosed with emphysema when he was in his 40s and kept up 3 to 4 packs a day of unfiltered PallMalls and Camels right until he was hospitalized the last time at 61. SOB used to get off the oxygen therapy at home and light up a cigarette still sitting next to the oxygen tank! Then the aftermath, estates and families, that's a joy, too. It's hard. Even if your parent isn't the best on earth, or just a plain old miserable abusive SOB like mine was, dealing with the death financially and emotionally is still painful and exhausting.
Take care of your mom. I know it's a burden but she's probably so lost. I was virtually insane for about four to six months after my mom died, just a total basket case mentally and I readily admit it. I remember I asked one person the same question once a week for four weeks in a row until he pointed out to me what I was doing. I had no memory of previously calling him. I missed bill payments, would burst out crying for no good reason, I was a total mess.