Hello,
Thanks for the query.
MCTD is a chronic autoimmune disorder.
The weakness of muscle is due to antibodies to muscle fibres, so its better to take rest and do mild exercises like walking, breathing exercise and stretching exercise.

Regarding diet, give him semisolid food which can be easily swallowed and after food he must sit upright or walk for at least one hour before going to bed.

This will prevent the chances of aspiration.
There is no particular diet which can help or which needs to be avoided.

Please XXXXXXX the rheumatologist and get his treatment started.

Let me know if you have any other doubts.
Thank you

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