Is this situation a gift with reservation

[Taxed to the hilt]

Parents gift a property to themselves and their son as joint tenants via a deed and parents pay all the household living expenses.

The son lives with the parents both before and at the time of the gift.

6 years after the gift the son decides to move out of the property and the parents do not pay the son a full market rent for his one third share of the property.

The parents both die more than 7 years after the gift.

When the father dies the house passes to the mother and son under the survivorship rules as it is held as joint tenants so there is a gift with reservation.

Is there a gift with reservation when the mother dies as before the gift she owned 3/6 of the house and after the gift they all the joint owners held 2/6 each but when the father died the mother owns 3/6 and the son owns 3/6 which is the same proportion as before the gift.

[maths]

Duplicate.

See other posting.