His brother was there, too, I believe, not just the mother.
We would have to know if the message was typed or handwritten. It could even be that he left no notes but someone else wrote them by hand or printed them. If SS was on his screen or search history, and he'd been dead awhile, then there was opportunity to stage things. Doesn't mean that's what happened, but it is possible, and in light of what he wrote on the forum that was the direct opposite, I think it's reasonable to have such suspicions. I wonder if the police fingerprinted the envelope and papers, and if they tried to determine whether the prints were from natural movements. I also wonder if there is an agenda in which LE is involved and the note was faked afterwards and added to the report, as it's not secret that UK coroners have previously called for action against this site. I know this heads toward conspiracy theory, which has negative connotations for a negative reason, but SS is highly provocative and a political target in case you haven't noticed.
I believe in reasonable assumption though. And the poster described it as "clearly" fraudulent, as if to suggest something that is only possible is highly probable/certain. I disagree with the probability, not the possibility. Even though I'm inclined to say the possibility is very slim due to having to consciously overlook so many details to convince myself it could be true, and not because I don't doubt the artifice of a political agenda, or the emotional need of grieving people to manipulate the facts as a coping mechanism (in fact it's because we're liable to [sub-]consciously change our own perception that I believe some think the note is forged, because the alternative for us is accepting betrayal/disingenuousness of posts that were to this forum's credit. I've had problems trying to understand that too in context because the outcries for our sanctuary's removal are somehow more hurtful coming from within than from complete outsiders who don't understand what it's like to be suicidal, well at least in my opinion).
Anyway, I would question who was involved in forging the note and the motive. Did the family do it, unbeknownst to the police? Or was it mutually agreed between the two parties? Or did a relative go rogue and do it? If the family or any one relative forged it independently, how far was it in hindsight? The house was evacuated by fire and police services upon finding the substance at the scene due to it being deadly in large quantities. The note points to a remaining amount of said substance being in an envelope. For this to be forged assumes the emergency services did not successfully purge the site of all SN during the evacuation and the family took advantage of what was left, and then bravely handled it from its container to an envelope, what they only perceive to be an extremely dangerous substance at that time for an evacuation to have been necessary. Unless the remainder was already left in the envelope by Joe, but no note?
I also question whether they'd be willing to forge a note that directly connotes they are not liable for his death, which if found by the police to be falsified evidence, is more incriminating for them than his posts and creates unwanted scrutiny towards their alleged innocence.
I don't think the authorities can mutually endorse a fallacy because for all they know if evidence of foul play did surface in later years, then the note's existence invalidates that, and perverses the course of justice, and scrutiny becomes directed at the police force itself. A potential media scandal. "Police accomplices in crime". Suicide forum was innocent all along.
I perceive too much at stake for an inside job, and it places much precedence on the opinions of the "victims". We already know what we think/want doesn't matter that much. To go lengths to make it appear Joe's final wish was this forum's closure when the wishes of previous victims have already been completely negated, including Callie Lewis', who despite posting hundreds of times saying she wished people understood the Right to Die was still portrayed in the BBC documentary to be incapable of rational thought, in order to have such views. Ultimately, whether Joe wanted us closed or not doesn't carry much weight in the greater picture of the movement against this forum.
Joe "loved" the community, but that doesn't equate to supporting the medium for the community, nor does being suicidal equate to not being pro-life. Also I imagine the prospect of nearing death can result in a complete overhaul of one's emotional values as the mind acclimatises to its perceived state of eternal non-being. Why did Edward the Confessor on his deathbed assure Harold Godwinson of his succession to the throne despite promising it to William Duke of Normandy prior? Leading to the Battle of Hastings. Though not the best example
Speaking of change of opinions, times like these I wish we had a Members Only section of this site because of the possibility of grieving relatives seeing this topic and finding it hurtful (at risk of sounding like I've considered everything above from a stance of pity)