Something you can do is find out what kind of relationship he is looking for by asking him.
The reason why he may be blocking you on social media when things seem to be going good is because he may be worried that you are getting too close and he just wants to slow things down.
So, he blocks you, then unblocks you when he feels enough time has elapsed to cool things off between you.
Hence, you both kinda have to start all over again.
Sometimes, a guy will act this way because he may have been hurt in a previous relationship and he has never dealt with it. Thereby, he does the blocking as a protective measure.
Hence, before you fall into the trap of falling for him or becoming very emotionally invested in him, you should ask him what kind of relationship he is looking for, if any.
If he can’t give you a straight answer, you may be better off abandoning your interaction with this guy.