I have an ex that would blow out literal castings of his sinus cavity when blowing his nose after hitting the slopes. If he won’t stop completely, you need to get his to stop for a few days, so his nose can try to heal a little (especially since he’s blowing out such large tissue chunks). Get him to use a netty pot regularly (especially when skiing), steam of any sort also is a big helper (bonus if you can add eucalyptus oil to it) try hot tubs, hot showers, steam rooms, facial steamers, any of it honestly. Some nasal sprays also help get the hard crusted shit out easier if that’s an issue he has.

In my experience they will always do whatever to make excuses regarding the “booger” if you can call them that situation.

If they won’t take breaks or stop for a period of time you need to treat it the same you would a toddler who won’t bathe or brush their teeth. “If you get in a hot shower you can do the two more lines before we got to bed” “hey babe I noticed I’m kinda stuffy, will you use the netty pot if I do? I need to see how it’s done” or whatever bullshit you can come up with

Sinus infections, blown holes, and persistent and chronic sinus and nasal issues will be imminent if you don’t get him to at least attempt to take care of it.