First I would ask how you’re going about them: Are they seeing the holes in their ideology and you’re looking to patch them with based diamat, or are they content with their ideology and you are looking to move them more radical? Ignore the moral implications to this question, what I’m getting at is there are different ways to go about convincing someone depending on how they are at the moment.

Either way be respectful and considerate of their preexisting ideology. If the former, suggest the reading materials other comrades have suggested. If the latter you can either wait for holes to become obvious or point out the discrepancies. If you do the latter on this then tread carefully and be respectful as they’re likely to take it personally as if it’s you who is tearing apart their ideology instead of the ideology itself natively possessing holes in it’s logic. I’ve found keeping it fact based and pragmatic takes the conversation away from personal interest in these theories and instead enforces a logical standardization removed from both parties in the conversation. They still might get pissed at you though. Just my 2 cents though.