13 year old son still sitting on his mother laps

ok so first off all I'm typing in english because I'm in the uk right know  . and i don't have that much of a time to figure out  and find  the swedish words . 

so the deal is i was in my friend last weak and she have an 13 year old kid she was siting on the computre and he want to see also what she see so he sit on his mother  " almost " in the nude like he was only in his boxers 

is that normal ??? for you mother I'm not a mother but is was a little odd to me !! 

will you thinks its ok ?!