These are common symptoms of THC withdrawal after someone has been seriously habituated. He might try melatonin for sleep and regular physical exercise is a major factor in recovery.
Also, keep in mind that recovery from issues with a neurological component take time. You wouldn't expect someone who got knee-replacement surgery to walk perfectly after 2 months.
The same goes for the brain, which is many times more complex. It is not uncommon for full recovery from withdrawal symptoms to take up to a year.
The important part is for him be disciplined and take care of his body and mind in the interim.
There is an excellent hub that may help your boyfriend: