Look up interoception. It's the 8th sense that tells us when we're hungry, tired, need to pee, etc. Some people just don't notice until it's too late. My son pooped in his pants until he was 9 or 10, but then we started enforcing a specific time (8 pm before bath) to sit on the toilet. Eventually it got better. (He's 13 now.) I agree with what other people said about cutting back stress.

Any new medicine? A few meds caused my son to have urinary problems. Other thoughts are urinary tract infection but uncommon in boys. If also increased thirst check for diabetes. Hang in there!

One of mine still does this at 9 years. Pretty sure it is stress, bit he will not say what is bugging him. He says that he does not feel the need to go and just ends up wet.

regression is normally associated with stress. Unless you stop the source of stress he is going to decline. This is true in our case- mine is almost 6 and will not feel or know that she has peed. It’s a neurological issue.

IS he in school if so it could be that there are no bathroom time. our children rely a lot on routine and once its altered it could disturb their activity. i hope you will discover what could be the issue. Sending you Hugs