Suggest you may want to do some LL training as this is basic stuff
No You cant force a tenant to leave on the day the notice expires. You have to do things legally. Illegal eviction is a criminal offence with fines up to £40,000 and up to 2 years in prison.
The only way you can make sure someone leaves is going through the correct legal processes, including serving the correct notices and then when these expire, going through the courts applying for possession, and ultimately when the courts give you a possession order, you can evict them using bailiffs. You cant tell how long it will take but on average from applying for possession to eviction when there is a tenancy takes 8 months. (That was when there was s21 may well take longer now under RRA with s8).
Just to check is the property in england, Scotland, wales or NI? Different regimes in different places in the uk
For england this is the process if there is a tenancy in place
Overview
You must follow the correct procedures if you want your tenant to leave your property.
You may be guilty of harassing or illegally evicting your tenant if you do not follow the correct procedures. Illegal eviction is a criminal offence that can lead to a prison sentence.
How to evict tenants
How you evict your tenant depends on whether you have an:
- assured periodic tenancy
- excluded tenancy or licence
- regulated tenancy
Assured periodic tenancies
To evict your tenant from your property, you’ll need to give them a section 8 notice.
If your tenant does not leave by the date in the notice, you’ll need to apply to the court for a standard possession order.
If your tenant does not follow the terms in the possession order, you can apply for a warrant for possession. This means bailiffs can remove your tenant from your property.
If the tenancy has ended and they are a trespasser there is also a process of applying to the court getting possession order using bailliffs etc
Previous thread If a tenant gives notice then doesn’t leave?
Despite his initial reaction, most people dont want to stay somewhere if they cant pay the rent be firm and business like with the father in law dont accept any sob stories and be clear he’s going to have to leave by 14 August and as he cant afford the rent on his own it’s better for him as well as you if he leaves instead of getting into rent arrears.
Good luck