My son has cancer of the tongue.  He is on a g-tube and needs to get more nutrition.  He has lost 60 pounds.  He is unable to swallow.  How can I convince him to get more nutrition than what he is taking now?  I have given  him liquid vitamin C and other supllements but I dont know if he is using them as he does not live with me.  I don' t like to pressure him .  Any advice???