Whether you're charged with a felony or misdemeanor for aiding and abetting the person who committed the crime will depend on whether the person committed a felony crime or a misdemeanor crime.
If the person you're aiding and abetting committed a misdemeanor crime such as theft or shoplifting then you'll probably only get charged with a misdemeanor for aiding and abetting the person in their crime.
If they committed a serious crime such as bank robbery or murder then you can be charged with a Felony yourself and if the person committed murder you can be charged with murder yourself even though you were never present when the person committed the murder.
Never hide a fugitive or aid and abet the person in their crime no matter how small the crime is.
The person is responsible and should be responsible for what they did and you shouldn't get yourself in trouble trying to help that person out in their crime.
If you know someone who's committed a crime and they show up at your house or you know there whereabouts you should turn them in so you don't get into trouble.