I have a friend and she is 15 and her boyfriend is 22 and her mother is in agreeable of them dating and the are not having sex is there a law for that

If both parents are agreeable and sex is not involved no law against it. But I question parents who would allow a 15 yr old to date a 22 yr old or a 22 yr old who would want to date a 15 yr old without sex involved.

At least in the US, there are no "dating" laws. OF course a 22 year old man and a 15 year old child have nothing in common and it is questionable at best.
Next I fully doubt any mother would allow or want their child with a 22 year old man.

Plus of course they will be having sex, what else would the 22 year old be interesting in.
Certainly not going to the Jr High School dance.

And at the beginning of course the 15 year old may "believe" the 22 year old does not want sex, that is how older men start and then slowly take advantage of the child.