My tenants sublease with his roomates. and regarding a 3 day notice to pay or quit?

I have a tenant who allowed another person to sublease, now the sublessor is not paying his share of the rent, can my tenant serve a 3 day pay or quit notice and if on the 4th day can he change the locks on the door or can we as landlords change the keys if requested by the tenant. And can our tenant keep the personal properties of the sublessor until they come up with the money? Is it ok for my tenant to change the locks on the doors if the rent is not paid as requested?