1.do you have funds 15000 CAD+ available at the end of closing balance 5000cad Per person for 10 days.. if not, then it is the issueYour son should apply on his own and should have no problem getting a TRV if he is continuing his studies in Canada after attending g grade 11. The major issue is there are concerns that the whole family or at least one parent will remain in Canada. Would only apply for one parent if you want to try and accompany your son to Canada.
2. Property can be sold any time money can be transferred any time. Fixed assets do not add value if the whole family is traveling together.
3. Same with Education your son could go back to india finish his high school and come back
4. You choose tourism yet you were intending to visit a relative memeber nephew. Why did you provide extra information? Who knows your relatives can you help you stay in Canada. Irrelevant information. If you say tourism, then stick to tourism. Thats why it is not consistent.
5. Sometimes luck plays a main role as well.
or if you were to apply again for tourism, apply by yourself, then visit canada and come back to india. Afterwards your stay in India and your wife/son can apply together.
just my thinking i can be wrong or true. You can apply for detailed refusal notes online then you will know exactly what went through the mind of the visa officer.