Is there something wrong with this

My dad just recently passed he was with my mom for 35 years and it was unexpected a stroke and cancer from 9/11 because he was a cop right where it happened and developed worse over time. Well long story short, my mom needs someone to sleep in the room with her for now because she never was alone and cry’s about missing him and don’t want her feeling alone because she lost her mom and husband and everyone else. My boyfriend judges me for sleeping in the room with her and says i’m 20 not a kid but he doesn’t understand why.. He makes fun of me daily. Advice please... He doesn’t even live with me so i dont know why it’s a big deal. maybe if i was a boy it would be weird, but i love my mom and don’t see a issue. as he isn’t close to his family.