I would expand upon Sean Johnson's excellent idea of having Matthew contact whoever alerted him about Matto and have them let his family know about this thread, as they may find comfort in knowing how much he was appreciated and respected here. Perhaps also the text of this thread could be compiled into a file (such as a pdf) and sent to the family through Matthew's contact. This is what funeral homes do with the online guest books they typically have on their web sites.
Greetings. I am the forum user who notified Matthew of the obituary, but I only knew Matto from online, and I don't know how to get in touch with his family.
Forum user seraphina has mentioned meeting him in person, so perhaps she might.
One thing I would caution, however, in terms of an earlier suggestion of having his family members read his posting history on this forum is that he expressed some views online that he acknowledged to me were very much at variance with his parent's beliefs. In prudence I will just say that there are certain things which might be hurtful for them to read.
The idea of compiling the testimonies from this thread into a pdf would probably be best. If his family cannot be contacted, then perhaps the remembrances could be sent to the funeral home to be posted on his memorial page. I will remember him for his singular insights, his wry sense of humor, and his tender
pensées on beauty and mystery.
Requiem æternam.