My minor sons name change

I was married to a Muslim man for 3 years and have been separated from him for almost 11 years and he hasn't been in touch with us at all since then. In which interim, I changed my son's surname to my maiden name at the Municipality. We haven't had a proper divorce since he imposed the triple talaq mandate on me and I don't have any papers to prove it. My son is thirteen years old now and has to go on a school trip abroad. Can I get his passport made as his legal guardian/mother using my surname which is also on all his valid documents like birth certificate,Adhaar card, school certificate under the new Supreme Court ruling citing that a fathers name is not needed anymore on a minor child's passport. However, on my passport I still appear as my ex's wife due to unavailability of required documents to prove our divorce and separation. From what I know, my husband had also applied for my son's passport many years back which was redundant it since we never utilised it. Will the records of that passport prove a problem to issue a new one for him? Please advise. Thank you.