Gascoigne, 45, who has spoken about alcoholism problems in the past and was sectioned five years ago under the Mental Health Act, appeared to be unwell and trembling at a charity appearance in Northampton on Thursday.
Schmeichel wrote on Twitter: "This is not fun watching. Gazza needs help. Come on PFA & (PFA chief executive) Gordon Taylor, time to step up.
"We are all responsible for how we live our lives. But that doesn't mean we can't step in and help, and I think the footballing community, as the family we at times claim to be, must do more to help Gazza and others like him.
"Instead of getting great deals on cars & other luxury goods for members, PFA should commit more time and funds to help the like of Gazza.
"So what if he's had help before and has messed it up, does that mean that we just give up on him?
"What really gets me here is people. Everyone close to him was looked after by him. Now he's abandoned by the lot and in many ways they helped him becoming what he is today. He needs help, they should be there to provide that for him, regardless."