He's not ready, so he is not ready.
Boys are OFTEN, later in this process.
I have a boy.
I just kept a potty chair, (because it is portable), out in any room my son was in. Just so he got used to looking at it and playing around it.
I didn't mention anything about it.
He knew what it was for.
Then when my son was ready... well, you will know.
Not forcing.
My son, did it on his own... and over TIME... the frequency of him going on it, increased, According to HIS timing of it.
Not mine.
Keep in mind, it can take MONTHS for a child to get used to it and the whole process.
AND it is a biological, process.
And night time dryness... is separate from day time pottying. Night time dryness, does not occur, until even 7 years old, because....it is a PHYSIOLOGICAL, development.
So until then, a child still wears night time diapers, for naps and bedtime.
Normal.
They do NOT get confused about diapers for sleep.
My kids, never did.
I simply tell them, their body is not ready to be dry at night.
AND I use, waterproof bed pads, directly under them, in case the night diaper leaks. AND for accidents.
ALSO keep in mind, that even if a child IS potty trained... a child DOES and will have, accidents.
NORMAL.
Even in Preschool/Kindergarten/1st Grade, ALL of my daughter's Teachers said, kids these ages, have accidents... at home, at school. It is normal.
This is childhood.
TOTAL 100% control over their bladder or bowels, are still, developing. Even if, potty trained.