Dont give them 2 months notice unless that's your requirement in your contract. This parent is going to be a jerk for the whole notice period so don't make it longer than it has to be.

You don't have to give a reason for terminating as long as you give the contracted amount of notice.

Dear Parent

Please be advised that this is formal notice that care for your child, NAME, is being terminated. As per the contracted terms, your final day of care will be DATE which provides you with one month's notice. Fees remain due at the normal scheduled payment dates.

Signed : Day Care