Magda, before your son ties himself in a box, how about reaching out to the person in admissions at each college he’s interested in and emailing them a copy of his current transcript and saying “I’d love to discuss a transfer application”. You can’t tell from a website if the 60 credit rule is a “rule of thumb”, an actual rule which 1 applicant in 30 years managed to get around, or is code for something else (like- you will need to pay for at least four semesters of college at our institution before we grant you a Bachelor’s degree so if you have more than 60 credits you probably will not find transferring here cost effective).
Email and then set up time to talk. Pointless to speculate.
Also, your son may find that these adcom’s are a wealth of information- like “we accepted 10 transfer students last year. We aren’t very transfer-friendly. But Brandeis (or Haverford, or JHU, or Conn College, or Wesleyan- I have no clue which colleges might be looking for kids just like your son) has a much stronger track record, particularly with kids from California so please call my colleague whose phone number is XXX and tell her I suggested that you reach out”.
Don’t spin. Make a phone call.