Hello I may assist.
You say that your friend agreed to pay £1260 a month in exchange for the person to look after his dog. The other person agreed and took the dog to look after.
You say My friend didn’t have the intention for a legally binding contract as he did not sign anything.
Unfortunately, that assumption is not correct. The contract does not need to be in writing. As long as there was a verbal agreement, that is more than enough to create a contract.
Any court would look at any action taken. In this case there is clearly an offer of payment £1260 month, the other person accepted that in exchange to look after the dog. Both parties were capable of creating a contract ie mental capacity and of legal age, and clearly there was an intention to create a contract. If there was not, the dog would not have been handed over to be looked after.
Therefore, your friend is legally bound to fulfill the terms as agreed and pay the debt.
There is no Force majeure because there is no written clause.
They could look at the term “Frustrated Contract.” However, this would fail, because the contract was made in the face of the covid19 outbreak.