Adding avocado oil baby weight gain

I was suggested to add avocado oil to my 10month soon 11 months son. Anyone has done this? She said a tlbspoon. Who has done this? I wonder how soon do we see a weight gain. How long will this process work and how ling have you continued on dojng this. I actually added half a tlbsp to his cereal and he ate it quick. Lol he never favored it only mixing his puree with it.

Fyi. His DRs! Not something i am making up. Perhaps i need to move this question with a group that are not having “normal” feeding situations. From around 18lbs to 17.4lbs in a month. Is not looking good track for him.