I would not push at this point.
I would be gathering info on various things he may want to consider as he makes his choice. Then I would say “I know you dont’ want to talk about which college yet but I have gathered info on things to consider when deciding when you are ready to talk about it.” Honestly until the end of April he doesn’t have to make a choice.
Also he probably won’t go wrong at any of the 4 choices…he may have a hard time because the differences will be so subtle to him.
Do look into requirements for him…like if there is a foreign language requirement and he hates that or a coop requirement or whatever.