unable to cope with his mother's illness, frank begins talking about fulfilling the wish in mo's letter, worrying joan. the next day, in more lucid moments, mo phones for minicabs to take her to colchester, calls which frank and dot cotton (june brown) have to cancel afterwards. joan and graham visit walford that day and joan suggests that she and graham take mo to stay with them temporarily, saying that the break may do mo's memory some good and give both frank and pat a chance to relax. however, when frank points out that mo's memory will never get better, joan accuses him of not wanting mo to get better. she and frank then argue, with frank accusing joan of only getting involved out of guilt, due to her estrangement from the family and ignoring mo after the death of their father. joan and graham then take mo to a restaurant, as mo believes that pat and frank are trying to poison her and refuses to eat another meal served there. afterwards, when joan leaves, mo begs her not to and hides from frank when he comes into the room, bursting into tears, believing he will kill her. after a brief talk with dot, it is decided that it is better for mo to go to colchester with graham and joan, and dot explains to frank that it will be better to let her go than to keep watching her decline. the three leave that night, and mo lives with them until she dies on 31 december 1992.