I, possibly am not the right person to answer this, as I can be very blunt.

Should you however lie to the authorities you will put yourself and your family in an insidious position. Records are kept, and so whatever you say will be recorded.

As for your friend, I only wish she had seen my SIL,(though thankfully there were no children) as she was the same, and eventually it killed her, about 5 years in all, 3 of which were beyond expectancy. Does she really want her daughter to see the complete mess she will be in when her organs start to fail.?

See if you can persuade your friend to seek help,offer your friendship if you can to support her if and when she sees the Doctor, lay the cards on the table. Her daughter deserves to have a mother, her husband deserves to have a wife. They all deserve to be a family.

Good Luck, I'll be thinking of you. This is not going to be easy by any means.