I think he should pull the barreled action, blast it with degreaser, blow it dry with canned air (don't freeze it), Easy to adjust a Jewell if you have that long, TINY, screw driver, then douche it in lighter fluid, let air dry,
getting the correct screw driver is the key. I bought mine from S&G Rifles many years ago from J.D. who is now dead. Jewel in San Marcos/ Sequin?? could sell you one too.
"I ain't here for a long time, I'm here for a good time"
King George Strait