After 3 years this month of not eating one bite of food nor having one sip of liquid,or as the doctors say: NPO status [Nil per Os= latin = nothing by mouth], I've become a reluctant student of liquid nutrition.
Like Brian Hill, I used Ensure Plus the first time around when i could not eat. But using prescription medicine for life with no real food was not acceptable. I do not have any idea of what is available or affordable for your family in Mexico but I'm assuming regular food is both.
There are many internet forums and website on blending food and putting it down a tube but I like this one. Bear in mind that this is NOT a cancer survivor group, nor focused on cancer in any way, but mostly mothers who are caregivers to children who need lifetime feeding tubes.
Food for tubies This link brings you to their forum but on the left is a box with four sublinks that explain the concepts
Hope this helps you if you can't get medical advice on it.
Charm