Neon Roberts' father said his son can get tired, and does need time to rest, but generally "he is his usual happy and playful self".
Neon Roberts underwent radiotherapy against his mother's wishes, after a High Court ruled last year that he should undergo the treatment.
A statement from Mr Roberts' lawyer added:
The surgery itself took a lot out of Neon and he is still dealing with some of the side effects of that treatment.
Overall, Mr Roberts has not seen a marked change in Neon or side effects beyond what the doctors expected.
This is what he and his family always hoped for.
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United in grief, the people of Manchester have come together in defiance to the suicide bomber who killed 22 people on Monday evening.
Hashem Abedi, who was held in Tripoli on the same day his father was arrested, was planning terror in the Libyan city, officials have said.
A notably mild night, feeling close and stuffy.