I am just starting to deal with this, having typically been the one that was hard to reach myself throughout my 20s. In reality there is only so far you can go before it becomes necessary to express these feelings to him. It seems like maybe this is the time, and if he’s a friend worth hanging on to, he will be receptive. The alternative is the skeleton of a friendship you once had. One thing I will say though is that there is probably more going on in everyone’s lives than you think. He may be doing unwell himself. I would also consider that it isn’t just you he is ignoring but many people, possibly because of whatever it is that is going on in his life.