If budget is a concern r.e. mom, that's a subjective issue. My dear mom was like that. If dad doesn't like fussy, again - kinda subjective.
Kagura, a tonkatsu specialist in El Segundo, is a good bargain to most. The meals can be quite large given the prices IMHO, and the quality is pretty much on par with the Torrance location. No wine to speak of though, but the sake selection is pretty good.
Second City Bistro in El Segundo has a broad wine list, very good food - nothing too fussy in my eyes - and prices might be just slightly high. Serving portions are more than adequate. Get the lamb chops if offered. The burger is delicious.
Ayara Thai in Westchester is very good for non-Thai Town Thai. It can be a little difficult to find if you're not familiar with the area - Google is your friend. They seem to always be very busy at dinner, so reservations would help. Most consider Thai food to be inexpensive. But Ayara is on the higher side for Thai cuisine of this kind. The bill can add up pretty fast for the budget conscious - almost everything is ~$10-15, and it's easy to order six-eight dishes for four here.
Truxton's is close to Ayara, and they have safe and relatively "more exotic" choices. I haven't eaten here in years so I couldn't give you a true opinion. But it might work with your dad - budget-conscious moms may be hard to deal with at anywhere but Norm's.