Perhaps you could ascertain "for sure" that the clothing in which he lay dead in a hospital bed was for a long enough time for cadaverine to form in the first place ...........and that his family kept those same garments, transferring them to the wardrobe and/or enabling them to contaminate sites in and around the apartment?
If you are keen to promote this speculation, it is at least proveable by acquiring information to back it up.
Now that is an interesting point you make Carew Quote - 'perhaps you could ascertain 'for sure' that the clothing in which he lay dead in a hospital bed was for a long enough time for cadaverine to form in the first place' unquote.
If as you say there needs to be a length of time for cadavarine to form, how long would Madeleine have had to be kept in the apartment for Cadavarine to form on the floor of the bedroom, also on Cuddle Cat?
According to Mr. Grime it is evident straight away after death.