O.P. you answered your own question at last. You have revealed the value of the house, at most, is the same as the charge (i.e. loan) secured against it. With Covid, let alone all the complexities, it is certain to be a minus sum. Don't waste a moment or thought, or a legal fee. Reject the inheritance.
Others have been right to urge you to go to lawyers. But that absolutely does not apply where you have nothing at stake to gain, and lawyers aren't free, so you have an open cheque to lose.
Of course there's an option to refuse legacy. (Otherwise, you could be left malicious gifts such as a houseful of worthless furniture to someone in a bedsit, or a delivery of manure.) But research, instantly, the process to reject legacy. Do it fast in case there's a time limit.
Do It Yourself if at all possible. It ought to be feasible for a layman. In the worst case, if you are forced to get a lawyer to sign, or witness, or file, you can get a quote for exactly that.
P.S. Arguably, law should be on-line easily searched and, in unusual exceptions, online N.H.S equivalent N.L.S. (national law service) specialists could chip in their experienced expertise. There's a curiously close match between professional medical and legal practices. Both can be good, bad or negligent, both can transform lives by doing the right and best-informed thing, or permanently wreck lives by being less than good .
However, doctors employed by the taxpayers don't usually gain financially from giving advice which deliberately exacerbates and prolongs the troubles of the customer. Trainee lawyers may very well have exactly as high (or low) moral ethics and intentions as trainee doctors, but both then run into the realities and traditions of disastrously continuing doing things the same old way, never whistleblowing.
Doctors bury their mistakes. Lawyers unfortunately get more money as a perverse incentive to prolonging and complicating cases, till the customers can potentially be, and sometimes are, left penniless and in impossible debt, with every possible asset stripped away for legal fees and court costs. It isn't the fault of practitioners that nobody, nobody in this country, is "equal before the law".