Are the sats on your side? If so, close and redeploy the sats. If everything is on their side, it is possible they are a mobile node and only come online to make a payment and then go offline again…so leave it alone. However, it’s possible they are a pleb whose node has bricked and they can’t get their funds, so force close and then funds are eventually returned to them on-chain. Best to see if they have contact info on 1ml or Amboss and reach out. Otherwise you must feel out the situation. To be sure, sats on LN do not like to be idle so I always default to freeing them.