Others have said it here: Get it treated! The treatment for this is usually very successful and is life-changing (for the better!)
I have had severe sleep apnea for many years. I believe I have had it since my college years, as I have had severe snoring since around then. Severe snoring is usually the dead give-away that you have it. I did nothing to investigate the cause of the severe snoring until I got to the point that when I woke up in the morning, it felt exactly as if I did not sleep at all. Like the walking dead. This went on for months, and was affecting every aspect of life.
Reported my condition to my doctor, who referred me to a doctor specializing in sleep disorders. Sent me to a sleep clinic, where I spent the night, with my body wired with many different sensors. Painless. A few days later, I went over the results with the sleep doctor.
Seems I would 'wake up' EVERY 50 SECONDS or so due to an apnea 'event', which usually means gasping for air due to obstruction. You become starved of oxygen and your body gasps for air, causing tremendous stress on the heart and brain, besides keeping your O2 levels below normal as well. With apnea, you never reach deep sleep (REM sleep), as you are constantly interrupted by the gasping / apnea. Men and women can both have it. Long story short, this is a very dangerous condition that is highly likely to shorten your life, as well as disrupt every aspect of it in the meantime. Can result in sudden death well before your time.
The good news, it is usually 100% treatable. In my case, a CPAP (continuous positive air pressure) machine made all the difference. IT IS A LIFE-CHANGING DEVICE! All it does is 'force' plain old air into your respiratory system at a prescribed (by doctor) pressure. I would not think of ever NOT using the machine when I go to sleep, or taking it with me when I travel, on vacation, etc. It has changed my life (as well as my brother's life, who I sent to the same doctor, btw).
(Search 'ResMed' and see the ResMed S9 as a current example of a good CPAP machine. There are MANY to choose from these days.)
I highly, highly recommend that your friend or relative get to a doctor immediately and get to a sleep clinic. Make sure your friend relates all the negative life problems encountered. The problem I most often see is that the machines can be expensive, so if one does not have insurance, the machines could be out of reach. If I were your friend / relative, I would get to the doctor, get to the sleep clinic, and beg, borrow or steal their way into treatment. Again, it will most certainly change your friend's life for the better. Easy-Peasey, no surgery (usually), no meds, just a little air pressure.
FYI, As far as I can tell, besides improving my general breathing, vaping has had no effect on my sleep apnea that I am aware of.
I sincerely hope this helps your friend.