Why Does My Friend Get Weird When Something Good Happens to Me?
People measure their own life almost entirely against whoever is standing closest to them. A friend goes strange after your win because of: 1) upward social comparison, your news just moved the benchmark he uses on himself 2) the self serving bias, he needs your luck to be luck and his own results to be effort 3) group ranking, every friendship runs on an unspoken order and you just changed yours. He is not unhappy for you. He is busy doing math.
The pattern
Your news changes his ranking
He congratulates you, then goes quiet
The jokes arrive a week later
Distance shows up without a fight
Myth vs Reality
Myth
A real friend is happy for you
Reality
A real friend tells you he is struggling with it. Most people just go quiet.
Tell him something that went wrong and count how fast he comes back.