Let's take this a bit at a time:

"It appears that his contributions over the years is greater than that distribution."

How do you consider that this applies to anything? Did he take the entire balance? Or, is the distribution not the full account balance? Because yes, over time, you tend to take distributions that are other than the full balance, and the full balance will reflect contributions +/- gain/loss. Nothing about the distribution of the Roth is compared to the contribution (basis), unless you have some other considerations, such as the person is under 59 1/2 and the funds in this account are newer than 5 years. Are any of these conditions present?

"Does that mean that although the distribution is taxable on the federal return,"

What makes this Roth distribution taxable? Roth distributions typically are not taxable, so you haven't given us some important details, apparently.

"none of it is taxable on the state return after subtracting his contributions over the years since he did not get a state deduction in those years."

Roths are funded with post-tax dollars, so there is no deduction for making them.

I would have to skip the MA question, since I don't know MA, and since some info seems to be missing here. Sorry. You can go to this link and scroll/find the Roth section:

https://www.mass.gov/service-details/view-non-government-pensions

"In addition his spouse received a Gross distribution for 2019 from her Roth IRA. Since she got no deduction for those contributions,"

Because Roth contributions are post-tax dollars. There is no "since" about it.

"do they also get subtracted on the same line C of Schedule X of the Massachusetts return resulting in only a portion of the distribution being taxed by the state?"

The portion distributed is only taxable based on failing to meet one of those Roth "rules."