Step son trouble

Hey I need some opinions on what to do. My partner and I have been together 9 years, he has 2 boys (14 and 16),we also have a daughter together. The 16 yr old has been living with us for about 4 years. A lot of things have happened and He has a non existent relationship with his mother/his brother. They haven’t really contacted him since Xmas. My partner and I try to Snapchat the 14 year old at least a few times a month. He hasn’t been to stay with us in 2 years, before lockdowns we would try to organise a day trip to go see him and he would dodge the question with I don’t know what we are doing that day ect. He hates me, will reply sometimes to my Snapchats but only 1 worded answers. I sent him a Snapchat of our daughter having toast for her 1st birthday and he replied shit is she a year already and I said yep she sure is and he never replied, no happy birthday or anything. My partner just told me tonight he hasn’t received anything wishing him a happy Father’s Day. I’m at the point of should I keep pushing to have a relationship with him in hopes that when he is older he will see the light or just see it for what it is? So conflicted.