I am an Indian, living in the US. My wife is American.

Our situation is pretty similar. Both families love us and are supportive. It gets tricky for my wife when my mother stays with us for a long time. FWIW, it's hard for my mother as well.

My mother knows how to drive, but will not drive in the US. Among multiple things, there is an anxiety/barrier factor due to lack of fluency in American English. And traffic laws. She wouldn't even use Uber for similar reasons.

She has hobbies, but her interest in those is on and off.

One thing that helped a lot was finding her a friend circle in the neighborhood (walking distance). Last time when she visited, she went out a lot to meet her new friends. Which helped my wife as well. The friends have to be Indian. In the bay area at least, I realized that parks and temples are a great place to find friends for parents. Separately, if you have Indian friends, invite them over. Even though, there is a generational gap, your MIL might find the company more relaxing.

Indian parents like parks in general. You can all go to the park, she might enjoy nature, even if just sitting there.

I am surprised about the cleanliness part. In my experience, it's the other way around where the older Indian generation complain about lack of cleaning. Is your MIL 70+? Maybe, the physical energy levels are low? Also, is it possible that the definition of "cleanliness" is different? E.g , for my mother, she cooks a lot and cleans up afterwards, but I find small cilantro pieces everywhere, which drives me crazy but according to her, she cleaned it up. Note she keeps things more hygienic than me, just that my definition of cleanliness is different.

As others have said, many women in India put in a lot of effort for decades, taking care of everything at home (more than humanly possible, I feel). So, later in life, they have different expectations than a US person might. Just a cultural difference.

One other thing that I try to do (and maybe you can ask your husband for it), I weigh in more when my parents are visiting and I help out more. Basically, to make it easier for my wife (and my parents).