Saget, who appeared with Loughlin in the hit ABC sitcom and its follow-up, Netflix's "Fuller House", tells the New York Post's gossip column Page Six he sent a text to his pal "a couple weeks ago."
"I love you and thinking of you - that's all," read the simple message, according to the publication.
He adds, "You know when it gets down to it, there's so much going on and so many people have gone through so much and you know... if you love somebody then you have to make that decision and (ask yourself), 'Is this something that causes me not to love a person?' And I love her. She's a sweetheart."
Lori and her designer husband Mossimo Giannulli have pleaded guilty to paying $500,000 (£382,000) to help their kids get into the University of Southern California as fake athletes as part of a major college admissions scandal, with Lori sentenced to two months behind bars and Mossimo ordered to serve five months.
The actress was also ordered to pay a $150,000 (£114,500) fine and perform 100 hours of community service, while Mossimo, the founder of his namesake clothing brand, will pay an additional $250,000 (£191,000) fine and serve 250 hours of community service.
Lori has been granted her request to serve her jail time at the federal correctional institution in Victorville, a medium-security prison in California. She and her husband have until November 19 to report to prison.