The 72-year-old, who sold the club to Moratti in 1995, believes that the Nerazzurri must remain in Italian hands and even offered his help in finding new investors.
"The Indonesian is only interested in business," he told the La Gazzetta dello Sport. "The club must stay Italian and be restructured, I can help find other entrepreneurs.
"I have nothing personal against Thohir, I don't know him and he has an enviable financial position.
"However, this situation saddens me because I would hate to see my favourite team end up in the hands of a stranger."
Thohir, who bought Major League Soccer franchise DC United last year, is reportedly looking to acquire a 75% controlling stake at the San Siro.