Personally if something like that every happened to me I would terminate them NOW and tighten my belt for the family budget until I filled the space ... at the most I would give them notice NOW if I thought I could stand looking at them for a couple weeks!
I personally have no use for abusive behavior specially in an adult they would be gone even if they did 'apologize' because IME that is not enough ~ saying hurtful untrue and vengeful things in anger is never acceptable ~ it is like driving nails into the soul! Someone can try to remove the nails with a 'sorry' but the holes they made are still there ... sometimes depending on the relationship if the behavior never occurs again they can heal over time but other times those holes never heal and the relationship can never be the same ... and more often than not people with that type of temper and lack of impulse control to say such things in the first place do not 'learn' and next time they get upset they will verbally attack you again cause it is in their nature and why would anyone want to surround themselves with people like that .... emotional abuse is still abuse and actually can be more harmful
IMO if you are still 'angry' enough about it to want to terminate them allowing them to continue in care until you get your ducks in order with a new client and than saying 'you are being terminated for something you did 7 months ago' just cannot end well ... in their mind they 'apologized' and are therefore off the hook and you risk being seen as both unreasonable and unprofessional for terminating them so 'late' after the fact and having them be angry about it ... if the apology is not enough for you to move forward without poor feelings TODAY than you should consider letting them go NOW while it is a natural consequence for their behavior! If there is a problem it should be dealt with immediately ~ if it warrants termination that should happen immediately or if you want to give the client a 'second chance' it should be made clear if it happens 'again' it will be immediate termination!
IMO what you are suggesting would be like if your child lost his temper and attacked a sibling today and he said 'sorry' so you let it go but than 7 months from now you punished him for it after the fact or if you behaved poorly in the office and you told your boss you were sorry and he let it go and waited to fire you for7 months down the road ... there is no way the person, even though they behaved badly in the first place, is going to accept that with grace when so much time has passed and they assumed the issue was 'resolved' and have moved on!
Or flip this scenario .... if the shoe was on the other foot and a provider did something a client did not like, the provider apologized and thought they made amends and a month or more passed and than got blindside by a client terminating them for it months later .... we would all be rubbing their shoulder and saying how wrong that is for them to have basically appeared to have accepted the apology while continuing to carry a grudge of mistrust and hurt towards the provider.