My daughter in-law is trying for baby number 2.
That is really nice that you are so concerned for your DIL! The short answer is yes.
The longer answer is that pregnancy stops the growth of Endo, and since your grandson is still so young, it is very possible that the Endo has not grown since she got pregnant with him or has only grown a little. Additionally, pregnancy can really reset the hormones and the body, so a lot of people who have trouble TTCing their first can go on to conceive their second fairly quickly.
However, there is also a chance that the endo HAS grown, especially if her periods have been heavy and painful since her fertility came back.
I had a lap (Endo surgery) myself in April, and my doctor removed some Endo--it wasn't too bad. I had to take it easy for about a week, but after that it was really fine.
GL with your DIL's TTCing efforts! Keep us posted!