In general, there are some exemptions that may apply to your situation, but may not, depending on the exact specifics.
In particular the two exemptions that seem relevant:
- If your wife and son are resident aliens, they may qualify for a resident alien exemption. They would need to be bona fide residents of India, or some other country, for the full tax year, or spend 330 days in any 12 month period there. (India does have a tax treaty with the US including a nondiscrimination clause, by the way.) It doesn't sound like this qualifies though as they're only out for 3 months.
- If they're not covered for a two month period, then they qualify for the short gap exemption. This is only a two month period though, if they're uncovered for three months you'd owe the penalty for all three months. So you could consider cancelling for two of the three months only, but three months wouldn't do.
I'm not including the "if you are here illegally" exemption, as I'm assuming you are here legally, but if you're not - that's also a reason to claim an exemption.
You can look at the full list of exemptions to see if you qualify for any others, as well.