Does a rent-free arrangement make her a tenant?

It will matter what the form of legal agreement is, and specific wording in that. I expect that is a Deed of Trust, rather than anything resembling either a lease or tenancy agreement. If a DoT without problematic wording, I don't see how you would have any liability before the property returns to your possession, but the unusual nature could easily make authorities suspicious that there is something underhand going on if they ever get involved.

You dont say what type of agreement was signed and whether it includes a conveyance if land, (ie some kind of lease). If not, then as the occupant is paying the cost of maintenance on the property, which you would otherwise have to pay for, then its possible, (maybe likely) that a judge would regard this as "monies worth" and rule that she has a tenancy, possibly an AST. This would mean that you would have all the obligations that go with the tenancy, including GSC, EICR, How to Rent, smoke and CO alarms and even s11 repairing obligations if the tenant failed to live up to the agreement she signed.

I'm surprised your solicitor didn't point out this possibility, but I would suggest you contact a specialist landlord and tenant solicitor to find out the full extent of any obligations you may have.

Reply to DPT.
The document is titled Deed of variation settlement agreement. (There were a few extra safeguards included ) that was written up by a "Specialist family law solicitor". Had my father NOT provided for his friend, she would have had a claim under the inheritance (provision for family and dependants ) act 1975 as she was financially dependant on dad. I am told that this arrangement is very common these days?. Basically, the act was bought in to stop people like dads friend being turfed out by the family making them a burden on the benefits system. Therefore, this arrangement could not be considered unlawful nor a tax dodge. I am not questioning the validity of our agreement. It works just fine. Just asking if this agreement is subject to the housing act or not?

For context. My fathers original will was written up by a "Specialist solicitor" that included his wishes to house his friend. However, the rest of the will turned out to be very vague and lacking much detail. The original solicitor had left the firm as did 6 other solicitors who I was passed onto until the estate was finalised. The "specialist solicitor " who wrote up the final agreement did not include any provision should I die before my fathers friend making me seek advise from another "Specialist solicitor" to rectify that. I have very little trust or faith in "Specialist solicitors"

Provision for family and dependents act has amendments from October 2014 which may apply to your situation.
Read up on internet

Reply to Kizzy.
Although the will DID include provision for his friend. The final agreement was written up to comply with the inheritance act as if it had not. I am not worried about the agreement. She can live there rent free for life. That is what my father wanted and I have no intention of breaking my word to dad by making her homeless. I think I will just get a gas safe check and electrical test done for my own piece of mind.

Reply to the comment left by Paul at 22/01/2025 - 10:50
Without wishing to put you off “doing the right thing“ and getting peace of mind, I wonder whether getting an EICR and a gas safety check could imply that you have assumed a landlord and tenant relationship, which could count against you and give you even more liabilities.

I would urge you to get proper advice before you do those checks.

Its your property at the end of day you need to protect it, with an EICR, Gas safety at least and any other repairs to keep its value, for when you eventually sell it. The occupier i would not be so concerned about as rent free, no strings attached, if passes away or ends up in a care home, is still not your problem !

Reply to the comment left by Paul at 22/01/2025 - 10:50
Get her to arrange the safety checks and you can always offer to pay.

What would bother me would be if the occupier goes into care home the council might try to place a charge on the title and you will have to prove the arrangements to the council which they might not easily accept.
There are elephant traps all over this imo.