The reason that is is a problem is that after Elly dies, her adult children and their spouses still won't be capable of functioning on their own. Since John clearly isn't interested in being his kind of a parent to a 'child' who can 'parent back' (which is to say 'kick John's dumb ass for him if he starts acting like the belligerent tool he is'), this means that he'll have to rely on someone to keep an eye on the children because, gosh darn it, they never managed to be able to look out for themselves for some weird reason.
This means that Gordon will end up with at least four adult foundlings to look after when Mrs Dr P dies and Dr P heads off to Florida to wait out the clock. Such is the price of accepting help from the Patterswine. Unlike a banker who will merely ruin his credit rating or a Mafia gangster who'll kick the shit out of him, Gordon has to end up wasting his life playing nursemaid to his pal from Grade Three and the rest of his siblings because he did something really stupid and accepted help from someone who thinks that someone else has to clean up his wife's mess for him.