Work experience need to be full time permanent to be counted for CRS points...
so ignore that 6 months while filling up ur work history section and include the same only in ur personal history while filing eAPR...
it won't be a problem.....
when you collect the experience letter (if it is with the same company) ask them to mention the from - to dates of internship and also 'from - to date of employment on permanent basis.
it is okay if you altogether avoid the mention of internship in experience letter as well...anyway don't put it under work history while creating EE profile...
get all the details in the experience letter as per CIC requirement
Full time paid internship can be counted towards the work experience. So if the NOC is same, he could get full points for the work experience.